Chapter Text
Leo’s knee ached. Not too badly, just enough to remind her it was there, like an itch she couldn’t quite scratch. She adjusted the brace absently as she walked through the lair, her fingers briefly brushing the worn straps. The ache wasn’t the problem, though. She’d been feeling off all day, like her head was full of static, her thoughts distant and slow-moving. It wasn’t like her usual anxiety, sharp and pressing, or the jagged edges of a bad memory creeping in when she least expected it. This was different.
She should probably talk to Donnie about it. Or maybe just sit down for a bit.
Raph was sprawled on the couch, half-watching a monster truck show, one arm draped over the backrest, looking completely at ease. Leo didn’t say anything as she dropped onto the couch beside him, grabbing the remote and flipping the channel without asking.
“Oi,” Raph said, but there was no heat to it.
Leo barely even registered the response. She settled in, Space Heroes lighting up the screen in all its dramatic, over-the-top glory. The sound of Captain Ryan’s voice was familiar, steady. Safe.
Her knee ached.
Her head felt fuzzy.
She pulled her feet up onto the couch, hugging them loosely to her chest. She didn’t usually sit like this—too closed-off, too vulnerable—but for some reason, it felt better right now. More comfortable.
She let the episode wash over her, barely processing the dialogue. The colors were bright. The explosions were fun. But something still felt wrong . Her fingers curled into the fabric of her knee brace, gripping it tightly for no real reason.
Raph shifted beside her. “You okay?”
Leo blinked. She opened her mouth to say yeah, I’m fine , because that was the default, the easiest answer. But the words stuck in her throat. Was she fine? She wasn’t sure.
Her brain felt… weird. Floaty. Heavy and light at the same time, like her thoughts were slipping away before she could hold onto them. She knew she should be able to explain it, should be able to put it into words, but everything was distant. Hard.
Her chest felt tight. She curled in on herself a little more, fingers gripping her knee brace even tighter.
“Leo?” Raph’s voice was softer this time.
“I dunno,” Leo mumbled. The words came out small. Too small. That was weird too.
Raph turned to face her fully, concern flickering across his features. “You feelin’ sick? Need Don?”
Leo shook her head, but the motion felt sluggish. “Just… fuzzy.”
Raph frowned. “Like dizzy?”
“No…” Leo hesitated. “Like… like my brain’s goin’ slow.”
That wasn’t exactly right, but it was the best she could manage. The fuzziness was spreading, creeping into her limbs, making her want to sink further into the couch. She felt warm. Heavy.
Safe.
The thought was strange. Usually, feeling weird made her less safe—like her body wasn’t under her own control. But this was different. She wasn’t panicking. Wasn’t scared. Just… small.
She didn’t understand it.
But Raph was watching her carefully, brows knitted together, and Leo didn’t want him to worry. She dropped her head onto his shoulder in an attempt to reassure him. It wasn’t something she normally did, but it felt right in that moment. She was too tired to question it.
Raph went still for a second. Then, slowly, he adjusted, shifting to give Leo a little more space to lean. “Okay,” he said, quiet. “Uh. Just lemme know if you need somethin’.”
Leo hummed in response. That was all she could manage.
She blinked slowly, staring at the bright, flashing colors on the screen, but she wasn’t really seeing them anymore. The sounds of Space Heroes had faded into background noise, like a distant radio playing in another room. She could still hear Captain Ryan’s voice, the dramatic explosions, the overly heroic music—but none of it was sticking .
Her brain wasn’t sticking to anything .
The fuzziness had settled deep now, threading through her thoughts like mist rolling in over a dark street. She tried to focus—tried to think —but her mind felt slow, syrupy. Like she was sinking into something warm and heavy, but she didn’t understand what it was.
She didn’t like not understanding things.
Her grip tightened on her knee brace again, fingers curling into the fabric like it was an anchor. A grounding point.
Raph’s shoulder was solid beneath her head. Warm. He hadn’t moved much, just kept sitting there, steady and quiet, like he knew she needed the stillness. Normally, Raph was not the still type. He was all motion, all restlessness, fists clenched and leg bouncing, ready to spring into action at any moment. But right now, he was here , and he wasn’t making a big deal about it.
Leo swallowed, but her throat felt tight. The weight in her chest pressed heavier.
What was happening?
She should move.
She should go.
That’s what she always did when things got weird—when her thoughts tangled up too tight, when the world felt too much . She pulled away, she found somewhere quiet, she let herself breathe until it passed. She was supposed to go to her room, shut the door, block everything out until she could fix herself.
But she didn’t move.
Something about the idea of leaving made her feel… wrong. Not scared. Not anxious. Just— wrong . Like some part of her knew she wasn’t supposed to be alone right now .
That didn’t make sense.
Did it?
Raph shifted beside her again, and Leo forced herself to lift her head just slightly, blinking up at him. His brows were furrowed, beak pressed together in concern, his gaze flicking over her like he was scanning for injuries.
“Still feelin’ weird?” he asked, voice softer than usual.
Leo hesitated. The words were hard to find, but after a long pause, she nodded.
Raph exhaled through his nose, glancing toward Donnie’s lab like he was debating whether to call them. Then he seemed to think better of it, turning his attention back to her instead.
“You want your weighted blanket?” he asked. “Might help.”
Leo froze.
Her blanket. The heavy one Donnie had helped her pick out, the one she kept in her room for nights when the world was too much , when her brain was too full of noise and static and pressure. She used it when she was overwhelmed, when her senses got too tangled, when she needed something to hold her down .
But this… this wasn’t that .
Was it?
She didn’t know.
She squeezed her hands together in her lap, her knee brace forgotten, and shook her head.
“No,” she said. The word felt small coming out. Too small. “No blanket.”
Raph didn’t push. He just studied her for a moment, eyes flickering over her like he was trying to figure out what was going on in her head. She wished she could tell him. She wished she knew.
Instead, she dropped her gaze, curling in on herself a little more.
She should go.
She should be in her room.
That was where she went when she felt wrong . That was the rule she had made for herself.
So why couldn’t she move ?
She tested it, shifting just a little, like she was preparing to stand up. But as soon as she did, her chest clenched, a deep, unfamiliar discomfort welling up in her gut. Her breath caught.
Leaving felt bad .
Not in the usual way, not like a panic attack creeping in, not like the pressure of a flashback pressing against her skull. This was different. This was… soft . Warm. Like something deep inside her was pulling her back down, whispering stay .
Stay with Raph.
Stay because Raph was safe .
The thought sent a shiver down her spine. It didn’t belong to her, not in the way her usual thoughts did. It felt separate somehow, like something inside her was curling up into a smaller space, something younger and fragile and in need of protection.
Leo swallowed hard, hands twitching in her lap.
What’s happening to me?
She didn’t realize she had started rocking slightly—just the barest motion, forward and back, like the ocean lapping at the shore. It was soothing. Grounding. She wasn’t even sure why she was doing it.
Raph noticed, though.
His expression shifted, something unreadable flickering across his face. But he didn’t say anything about it. He just leaned back into the couch, letting himself relax, making sure she knew he wasn’t going anywhere.
That was good.
That was… really good.
Leo exhaled shakily, finally letting herself settle.
~~~~~~~~~~
Raph was trying really hard not to freak out.
Leo was still curled up next to him, still pressing herself into his side like she needed the contact, but something was off . Worse than before.
Her rocking had slowed, but her hands were twitching in her lap, fingers clumsily rubbing together like she was trying to grab something that wasn’t there. Her eyes had that faraway look, hazy and unfocused, like she wasn’t fully present.
“Leo?” Raph tried again.
Leo blinked up at him, but her face was softer now—relaxed in a way that made something cold twist in his gut. Her usual tension, the sharp focus she always carried, the ever-present stress pressing into her shoulders—it was just gone . Like she had let go of something.
She opened her mouth, and Raph’s stomach dropped .
“Raphie,” she mumbled, her voice suddenly high-pitched and soft, like she wasn’t trying to sound different, just… was .
Raph stiffened.
“…What?”
Leo blinked up at him, eyes wide. She shifted a little, like she wanted to say more, but when she finally spoke again, the words were wrong .
“’M sleepy,” she mumbled, rubbing at her eyes with her fists. “Wanna stay hewre.”
Her voice was tiny .
Her words were slow, slurred—not like she was hurt, but like she wasn’t bothering to think too hard about them. Like she was…
Raph didn’t even know what was happening.
Something in his chest clenched.
“Leo,” he tried, voice steady but urgent. “You okay? Somethin’ hurt?”
Leo blinked again, clearly not understanding why he sounded so worried.
“Nuh-uh,” she said, shaking her head too fast. “’M fine, Raphie.”
Raffy.
Raph felt a little lightheaded.
This—this wasn’t right. Leo never talked like this. Never shortened her words like that, never slurred her speech unless she was really exhausted, never made her voice all high and soft like—
Like a little kid .
Raph’s pulse kicked up.
Okay. Okay, nope . Something was wrong .
“I’m gettin’ Don,” he said, moving to stand.
Leo perked up immediately .
“Donnie?” she gasped, her whole face lighting up like a kid who had just been promised ice cream.
Raph froze.
That—what— what the hell was happening?
Leo had never, ever reacted to something like that before. Not since they were kids.
And even then —
Raph swallowed hard and didn’t waste another second.
“Stay right there,” he muttered, pushing himself up off the couch and hurrying toward Donnie’s lab.
Leo didn’t protest.
Actually, she started kicking her feet back and forth, humming to herself.
What the hell.
“DON!”
Donnie barely had time to look up from their workbench before Raph skidded into the lab, breathing hard.
“Something’s up with Leo.”
Donnie immediately straightened, dropping whatever they were holding. “What? What happened? Is she hurt?”
“I—I dunno,” Raph admitted, running a hand over his face. “She’s actin’ weird —talkin’ weird. I don’t—I don’t know what’s wrong.”
Donnie didn’t waste time with questions.
They followed Raph straight back to the couch, heart pounding, already running through worst-case scenarios in their head.
If Leo had hit her head without realizing it—if she was slurring her speech—if she was losing cognitive function—
But then they saw her.
And she was smiling .
Wide, bright, giddy .
As soon as she spotted them, she squealed.
“DONNIEEEE!”
Donnie stopped in their tracks .
Their brain flatlined.
Leo was—was grinning at them.
Wiggling excitedly where she sat.
Kicking her feet.
Leo— their Leo , their hyper-logical, over-serious, anxious older sister —was sitting there looking like an actual toddler .
Raph shot them a panicked look. “See?”
Donnie was too stunned to respond.
Leo, meanwhile, was still beaming at them, like she was waiting for them to pick her up or something.
They cleared their throat, forcing their brain back online. “Uh—Leo, I’m gonna check you over, okay? Just—just to make sure nothing’s wrong.”
Leo blinked. “Nothin’s wrong.”
Her voice was so small.
Donnie swallowed back the growing concern in their throat and knelt down, running through basic checks—pulse, temperature, checking her pupils, pressing two fingers gently to her wrist.
Everything was normal .
Physically, she was completely fine .
Which meant—
Donnie sat back, frowning. “I don’t understand.”
“What the hell do we do ?” Raph demanded, hands on his hips. “I thought she was havin’ a stroke or somethin’, but she’s just sittin’ there bein’ all—”
Leo interrupted him with another gasp .
Both of them turned in time to see Mikey skipping into the living room.
“What’s all the noise about?” Mikey asked.
Before Donnie could even start to explain, Leo squealed again.
“Mikeyyyyyy!”
Mikey barely had time to react before Leo practically threw herself off the couch and into her arms.
Donnie and Raph stared.
Mikey—somehow completely unfazed—just caught her and hugged back , squeezing her tight. Leo nuzzled into Mikey’s shoulder, clinging onto her like a koala.
Donnie’s jaw dropped.
Mikey glanced over Leo’s head, giving Donnie and Raph a confused look. Raph just shook his head, looking deeply unsettled. Donnie sat back on their heels, still piecing it all together.
Leo was acting like a little kid. She wasn’t injured. She wasn’t sick. She wasn’t drugged.
So what—
Then, suddenly, everything clicked .
Oh.
Oh.
Donnie inhaled sharply, shifting to face Leo.
“Leo,” they said gently. “How old are you?”
Leo didn’t hesitate.
“Four!” she said, beaming.
Like it was the most obvious thing in the world. Raph and Mikey exchanged startled looks.
Donnie sat back, exhaling. “Okay. Okay, I think I get it.”
Raph’s eyes snapped to them. “ You do?! ”
Donnie nodded, rubbing at their temples. “I think Leo’s experiencing age regression.”
Mikey blinked. “Like… mentally?”
Donnie nodded.
Leo just hummed happily, still curled up in Mikey’s arms.
Raph looked deeply skeptical. “The hell is that?”
Donnie sighed, choosing their words carefully.
“Age regression is when someone’s mind temporarily reverts to a younger state, usually as a response to trauma or stress. It’s not something they control—it just happens when their brain is overwhelmed. It’s… it’s a coping mechanism. A way to feel safe.”
Raph’s brows furrowed, eyes flicking to Leo. Leo, who was now playing with the ends of Mikey’s mask tails. Leo, who looked so relaxed, so at peace .
“So… she’s not stuck like this?” Raph asked.
“No,” Donnie reassured. “She’ll come back when she’s ready.”
Mikey bounced Leo a little in her arms. “Well, if she needs to be little right now, then she’s gonna have the best little time ever.”
Leo giggled.
Raph was gonna bolt. Not because he didn’t care—he did —but this? This was way out of his comfort zone.
Leo was still clinging to Mikey, completely happy and content, her little arms looped around Mikey’s neck, swinging her feet. She was fine . Donnie understood what was going on now. Mikey had immediately adapted like it was second nature.
So Raph? Raph was not needed here. He started backing up, hands raised. “Welp. Looks like you two got this handled, so I’m just gonna—”
“RAPHIE!”
Raph flinched.
Leo’s head snapped up, her wide, watery blue eyes locking onto him with laser focus.
Uh-oh.
“Where go?” she demanded, her tiny voice wobbling slightly.
Raph stiffened. “Uh. Just—y’know. Givin’ you space.”
Leo’s lip trembled.
Oh, hell no .
Mikey and Donnie both looked at him like he was an idiot.
Raph panicked. “I—uh—fine! I’ll stay!”
Immediately, Leo brightened, the pout disappearing as quickly as it had come. “Yay!”
Raph exhaled sharply through his nose. Manipulative little gremlin.
Leo reached up, arms outstretched, grasping at the air. “Up.”
Raph hesitated. He wasn’t really a hug guy, not the way Mikey was, but…Leo gave him the biggest, saddest, puppiest eyes he had ever seen. Raph sighed. He was so weak. With some hesitation, he leaned down and scooped her up, immediately cursing himself when she latched onto him like a koala, nuzzling right under his chin.
“Comfy,” she mumbled.
Raph felt himself melt just a little .
Mikey snickered. “Awww, she loves you, Raphie.”
“Shut up .”
Leo just hummed happily, pressing her face into his neck.
Raph huffed, adjusting his grip on her. “A’ight, what now?”
Leo suddenly perked up, lifting her head. “Hun’gry.”
Mikey gasped dramatically. “OH NO! We can’t have that! What does our baby princess want to eat?”
Leo giggled at the nickname, swinging her feet again.
“Apple juice,” she said immediately. Then, after a second of thought—“An’ fishy cwackews.”
Mikey saluted. “Apple juice and fishy crackers, coming right up !”
With that, she turned and pranced off toward the kitchen.
Leo watched her go with big, eager eyes before getting off of Raph and tugging on his mask tails. “C’mon, Raphie! C’mon Dee!”
She didn’t even wait for them to agree, she just dragged them back to the couch, shuffling and pulling until Raph finally gave up and flopped down. Leo climbed into his lap, nestling herself comfortably against his plastron, her hands gripping his arms.
Raph sat there, frozen. He did not know what to do with this. Leo was never this touchy. Leo barely even let people pat her on the back most days. Now she was fully snuggled into him, content as could be, like she belonged there. Raph hesitantly put a hand on her shell, patting it awkwardly. Leo chirpped happily.
Donnie sat next to them, watching all of this unfold with mild amusement. “I have never seen you so affectionate.”
“Shut up, Don.”
Leo hummed, shifting again to press her face against Raph’s arm.
Raph glanced down at her, unsure. “You good, squirt?”
Leo giggled.
“Not squiwt. ‘M Leo.”
Raph smirked. “Yeah, yeah, I know that.”
Leo beamed.
Donnie watched this for a moment before deciding to run some little tests—nothing invasive, just… questions. They were still trying to understand exactly what was happening.
“Leo,” they said gently, “can you tell me what you did today?”
Leo blinked up at them, big and innocent.
“Uhhhhh…”
She paused.
“Dunno.”
Donnie nodded, expecting that. “That’s okay. Can you tell me your full name?”
Leo frowned in concentration. “Leonawdo Hamato.”
Her words weren’t super clear, but Donnie could understand them well enough.
They nodded again, keeping their voice calm and encouraging. “Good job! What about your favorite color?”
Leo gasped, looking personally offended that they even had to ask.
“Bwoo!” she chirped.
Raph snorted. “No kidding.”
Leo just smiled up at him, looking ridiculously pleased with herself.
Donnie hummed, thinking. “Do you know how old you usually are?”
Leo blinked at them.
Then, after a pause—
“…Four.”
Donnie shook their head. “No, I mean—when you’re not feeling little. How old are you then?”
Leo scrunched her face up in deep thought.
After a solid ten seconds, she shrugged.
Donnie exhaled. “Okay. No worries.”
It was official. She was fully regressed.
“Alright,” Donnie muttered, running a hand through their mask tails. “That confirms it.”
Raph raised an eyebrow. “Confirms what ?”
Donnie looked at him.
“This isn’t just her playing around,” they said. “She’s fully regressed—she doesn’t even remember being older right now.”
Raph frowned. “So… she really thinks she’s four?”
“Yes,” Donnie confirmed. “Her brain has completely slipped into a younger state. She’s not pretending —she’s experiencing being four.”
Raph looked down at Leo, who was still cuddled into his side, idly playing with his fingers.
It was so weird seeing her like this.
He nudged her lightly. “You sure you’re four, squirt?”
Leo nodded eagerly. “Uh-huh! I ‘sware! ”
Raph let out a long breath.
“Well,” he muttered, shooting a look at Donnie, “guess we got a baby sister for a bit.”
Leo giggled. “Yup!”
Donnie shook their head with a small smile. “I guess we do.”
Mikey suddenly popped back in, holding a juice box in one hand and a bowl of goldfish crackers in the other.
“Alright, who’s ready for a snack?!”
Leo gasped dramatically , reaching for the juice box immediately.
Raph rolled his eyes, but he couldn’t stop the fond smirk that tugged at his lips.
Leo was perfectly content. She was curled up in Raphie’s lap, warm and safe, sipping her apple juice through the little bendy straw. Her fish crackers were so yummy—salty and crunchy, and shaped like little fishies!—and Space Heroes was playing on the big TV with all the cool ‘splosions and Captain Ryan saying super cool things.
She kicked her feet lazily, perfectly at peace. She didn’t notice her siblings exchanging glances. Didn’t pay attention when they all slowly, cautiously started talking, their voices quieter, more serious. Didn’t realize they were talking about her .
“She’s totally checked out,” Donnie murmured, watching Leo with quiet fascination.
“Yeah,” Raph muttered, arms still loosely wrapped around Leo’s frame. “Kinda freaky, not gonna lie.”
Leo was right there —but at the same time, she wasn’t .
Her little fingers were busy pinching up goldfish crackers one by one, dunking them into her mouth, her whole focus absorbed in her snack and her show. She wasn’t paying attention to them at all.
It was so un-Leo-like that it made Raph’s skin itch.
Mikey, sitting cross-legged on the couch beside them, rested her chin in her palm. “So… what do we do?”
Donnie exhaled, rubbing their temples. “First, we need to figure out why this happened.”
Mikey frowned. “Did something trigger it?”
Raph shook his head. “I dunno, man. We were just watchin’ TV, and then she started gettin’ all quiet and clingy. Next thing I know, she’s talkin’ like a baby and lookin’ at me like I hung the damn moon.”
Mikey snorted. “She does love you the most.”
Raph rolled his eyes, shifting a little as Leo pressed further into him. “Yeah, I’m seein’ that.”
Donnie hummed thoughtfully. “It could have been building up all day. She said she was feeling ‘fuzzy,’ right?”
Raph nodded.
“That could have been her brain preparing for the regression,” Donnie theorized. “Like… her mind was trying to protect itself from something.”
Mikey tilted her head. “But what ?”
Donnie sighed. “We know Leo has PTSD. She’s had years of trauma and stress and leadership pressure weighing on her. It’s possible her mind just… couldn’t handle it anymore. She might have needed an escape.”
Mikey frowned, looking down at Leo. “So… her brain made her little?”
“Basically,” Donnie confirmed. “Age regression is a coping mechanism. The brain reverts to a younger state when it feels unsafe or overwhelmed. It’s not something she’s doing on purpose—it’s an involuntary response. Like dissociation, but… different.”
Raph’s brow furrowed, looking down at Leo again. “But she feels safe now?”
“She must ,” Donnie said, watching as Leo wiggled happily, completely engrossed in her show. “Regression is usually a survival instinct. If she’s fully regressed like this, it means she feels secure enough to let herself be vulnerable.”
Mikey leaned back against the couch. “Damn.”
“Yeah.”
A beat of silence stretched between them.
Then Raph cleared his throat. “So… is this, like, a one-time thing, or…?”
Donnie chewed on their lower lip, thinking. “It’s hard to say. Since this is her first time regressing—at least that we’ve seen —it’s possible it was just a one-off reaction to something stressful. But…”
“But what?” Raph pressed.
Donnie hesitated. “If her brain needed to do this to cope once… it might happen again.”
Mikey perked up. “So this could be, like… a thing now?”
Donnie nodded. “Possibly. We won’t know for sure until we see how she is when she comes back. But if this does become a recurring thing, we need to be prepared .”
Raph groaned, dragging a hand down his face. “What, like—what does that mean ? We gotta get baby stuff now?”
Donnie winced. “I mean… maybe ?”
Mikey gasped. “WE GET TO GO SHOPPING?!”
Raph groaned again. “Oh my God , Mikey.”
“I’m just sayin’!” Mikey grinned, throwing up her hands. “If our big sister is gonna have little baby moments, then we gotta make sure she’s comfy, right? Right? ”
“…I hate that you’re making sense.”
Mikey beamed.
Donnie sighed. “Okay. If we are preparing for future regressions, we should make a list of what we might need.”
Mikey was already bouncing in place. “OOH! OOH! I GOT IDEAS.”
Donnie pulled out their phone, ready to take notes. “Alright. Hit me.”
Mikey clapped her hands together, thinking. “Okay, so, first— snacks .”
Raph scoffed. “She literally already has snacks.”
“Yeah, but baby Leo probably has different snack tastes,” Mikey pointed out. “We should ask her what she likes best when she’s little.”
Raph sighed. “Fine. Snacks.”
Donnie typed it in. “What else?”
“A sippy cup,” Mikey said immediately.
Raph made a face . “Are you serious?”
“Dude, look at her.”
They all glanced at Leo, who was still sipping happily on her little juice box, occasionally getting distracted and holding it with both hands like it was the most precious thing in the world.
“…Okay, fine,” Raph admitted. “She would like a sippy cup.”
Mikey smirked. “Told ya.”
Donnie added it to the list.
“What else?”
“Soft stuff,” Mikey said, snapping her fingers. “Like blankies and plushies and stuff she can snuggle.”
Raph blinked. “She already has a weighted blanket.”
“Yeah, but that’s different,” Mikey argued. “That’s for big Leo when she’s overwhelmed. But baby Leo? She might want, like… a soft blankie. Something fuzzy and warm. And maybe a stuffed animal!”
Raph’s mouth opened—then closed again.
Leo did seem way more snuggly in this state…
“…Fine.”
Donnie was already typing.
Mikey hummed, thinking. “What else do little kids like?”
Raph snorted. “Hell if I know.”
Mikey’s face lit up. “TOYS.”
Raph choked. “Are you serious?!”
“YES,” Mikey insisted. “She might wanna do stuff when she’s little! Like coloring or playing with blocks!”
Donnie tilted their head. “It might not be a bad idea. It could help her self-soothe.”
Mikey grinned .
Raph sighed, defeated. “Fine. Whatever.”
Mikey giggled, practically vibrating in place. “I can’t wait to take her to a toy store someday.”
Donnie snorted. “Let’s not get ahead of ourselves.”
Mikey winked.
Donnie finished typing the list and looked at them both. “Okay. So if this does happen again, we know a few things—one, she needs comfort and familiarity. Two, she’s the most attached to Raph. And three, we need to make sure she’s safe while regressed, since she’s in a more vulnerable state.”
Mikey saluted. “Got it, boss.”
Raph exhaled sharply, looking down at Leo again.
She was so at peace like this.
And if she needed this to feel safe, if this was how her brain was protecting her from all the bad things in her head…Then Raph would deal.
Leo sucked the last bit of apple juice from her straw, letting out a satisfied sigh as she leaned back against Raphie’s plastron. Her tummy was warm and full, her fingers still idly playing with the crumbs at the bottom of her bowl.
She was so comfy.
So when Dee clapped their hands together and said, “Alright, I think it’s bedtime,” Leo’s good mood instantly soured.
Her face scrunched up in protest.
“Nooo…” she whined, tucking herself further against Raph.
Mikey giggled. “C’mon, baby sis! We gotta get you all snuggled up in bed so you can be all warm and cozy.”
Leo shook her head. “No sweep.”
“Yes sleep ,” Donnie corrected gently, standing up. “You’ve had a big day, little bug.”
Leo pouted harder, nuzzling deeper into Raphie’s arms. “Not sweepy.”
Raph huffed. “You literally just yawned two seconds ago.”
Leo gasped dramatically. “Did not!”
Donnie rolled their eyes. “Okay, fine. But even if you’re not sleepy, it’s still bedtime.”
Mikey bounced up from the couch. “I can tuck you in!” she offered cheerfully.
Leo froze.
Then, suddenly, her whole body tensed.
“No,” she said firmly, voice small but serious.
Mikey blinked. “What?”
Leo clung to Raph’s arm, shaking her head, her hands gripping his wrist like her life depended on it.
“No, no, no, no, no.”
Mikey put her hands up. “Whoa, okay, it’s cool! I won’t tuck you in if you don’t want me to.”
But Leo wasn’t calming down. Her breath was hitching, her fingers squeezing tighter, and her eyes were starting to glisten.
Raph felt his stomach drop.
“Whoa, whoa, whoa,” he murmured, shifting her slightly in his lap. “Hey, what’s wrong?”
Leo let out a tiny, distressed whimper. “No Mikey.”
Mikey frowned. “Do you—do you not want me to tuck you in?”
Leo shook her head aggressively.
“Okay, okay,” Mikey said quickly. “That’s okay, baby, I promise. No Mikey tuck-ins.”
But Leo was still on the verge of tears, her little breaths coming faster.
Raph tightened his hold on her instinctively. “You okay with me tuckin’ you in, squirt?”
Leo sniffled.
Then, after a pause—she nodded.
Raph exhaled. “A’ight. Then let’s go.”
He stood up, scooping her into his arms as naturally as if he’d been doing this forever.
Leo immediately latched onto him, hiding her face in his shoulder, her arms winding around his neck.
Donnie and Mikey followed as Raph carried her to her room, neither of them saying anything.
Once they got there, Raph carefully laid her down in bed, making sure to tuck her into her blankets just right .
Leo let out a soft, sleepy sigh, her little hands gripping the edges of the blanket.
Without even thinking, Raph reached over and flicked on her galaxy projector.
The dark walls of her room instantly lit up with soft blues and purples, swirling stars and galaxies dancing across the ceiling.
Leo hummed happily, watching the lights with drowsy eyes.
Donnie and Mikey leaned against the doorway, watching as Raph crouched beside the bed.
“Alright,” he said, keeping his voice soft. “You good now?”
Leo nodded, eyes fluttering closed.
Mikey smiled. “G’night, baby sister.”
Donnie crossed their arms, a rare softness in their voice. “Sleep well, little bug.”
Raph hesitated—then reached forward, brushing a hand over her head.
“Night, squirt.”
Leo hummed again, barely awake.
Her tiny voice mumbled something.
“…Night-night, Raphie.”
Raph swallowed thickly.
Then, with one last look at her peaceful little form, the three siblings quietly left the room.
As soon as they were back in the main part of the lair, Raph let out a long breath, running a hand over his face.
Mikey flopped onto the couch. “Whew. That was… something.”
Donnie sat down beside her, fidgeting with their fingers. “So, if she wakes up still regressed, we should probably have a plan.”
Raph leaned against the wall, arms crossed. “Like what?”
Donnie sighed. “Well, if she’s still little in the morning, we need to make sure she eats, gets dressed, and stays safe. We should also be ready for any mood swings—little kids are unpredictable.”
Mikey nodded sagely. “Big facts.”
Raph frowned. “And if she does wake up normal?”
Donnie pursed their lips. “Then we play it by ear. She might not even remember regressing.”
Raph’s stomach twisted at the thought.
Mikey sat up. “Okay, but if she does stay little for a while… do we need to, like, do anything special?”
Donnie sighed. “For now, I think we just have to follow her lead. If this happens again, we’ll adjust as needed.”
Raph grumbled but didn’t argue.
After a moment, Donnie stretched. “Alright. We should all get some sleep.”
Mikey groaned. “Ugh, fine .”
The three of them parted ways, heading off to their own rooms.
~~~~~~~~~~
Raph had just started to doze off when it happened.
A scream.
High-pitched, raw, desperate .
Then—frantic, terrified chirps .
Raph was out of bed before he even knew what was happening.
His heart pounded as he dashed through the lair, his blood running cold as he realized where the sound was coming from.
Leo’s room.
He burst through the door, his eyes scanning the dark.
Leo was curled up in her blankets, trembling, her body slightly retracted into her shell.
Her whole frame shook with little hiccuping sobs, chirps still spilling from her lips, desperate and frightened.
Raph’s chest tightened.
He’d heard that sound before.
That soft, instinctual cry for help.
It was the same sound she made when she was scared out of her mind .
“Leo?” he called, stepping forward.
Leo flinched, barely peeking out of her shell, her big blue eyes glossy with tears.
“Raphie…” she whimpered.
That tiny voice— still little .
Raph moved .
He climbed into the bed without hesitation, scooping her up and pulling her into his lap.
Leo latched onto him, burying herself in his plastron, her little hands clutching at him like he was the only thing keeping her grounded.
Raph rubbed slow circles into her shell, whispering reassurances. “Shh, I gotcha. You’re okay. You’re safe , squirt.”
Her little sobs quieted slightly, but her breathing was still shaky.
After a long moment, Raph leaned back slightly. “What happened, baby girl?”
Leo sniffled, rubbing at her eyes.
“Scawy man,” she mumbled.
Raph’s stomach dropped.
He didn’t even have to ask.
He knew .
“…Shredder?”
Leo whimpered, nodding, her hands still curled into his arm.
Raph exhaled, pressing a kiss to the top of her head.
“He’s gone, squirt,” he murmured. “He can’t hurt you no more.”
Leo didn’t respond, just curled tighter against him.
Raph sighed, adjusting her so she was fully resting against his chest.
“Alright,” he muttered, settling in. “Guess I’m stayin’ here tonight.”
Leo let out a soft hum, her fingers gripping his wrist like a lifeline.
Within minutes, her breathing evened out, her small body finally relaxing. Raph rested his chin atop her head, letting his eyes drift closed.
~~~~~~~~~~
Leo woke up feeling… off .
Her head was groggy, her limbs heavy, and her blankets were unusually warm. She shifted slightly, stretching out her legs, only to realize—
Something was next to her.
She froze.
Her breath hitched as she lifted her head, blinking through the haze of sleep. Her vision slowly focused, adjusting to the dim light filtering into her room.
And then she saw him.
Raph.
Lying right next to her, his large frame half-sprawled across her bed.
Leo stiffened.
What the hell?
Raph wasn’t even asleep. He was reclined against the headboard, one arm draped lazily around her, scrolling through his phone with a look of pure exhaustion.
Leo’s brain stuttered.
“…Raph?”
Raph’s eyes flicked away from his screen. He barely looked up before greeting her casually—
“Mornin’, squirt.”
Leo blinked.
Squirt?
Why was he calling her that? He never called her squirt . That was Mikey’s nickname, not hers.
She stared at him, still half-curled against his side, still feeling groggy and wrong .
“…What?”
Raph finally looked up fully. He stared at her for a second, scanning her expression. Then his brow furrowed.
“Oh,” he muttered. “You’re back.”
Leo tensed.
“…Back from what ?”
Raph exhaled, locking his phone and stretching. “Yeah, okay. Don should explain this one.”
Leo narrowed her eyes. “Explain what ?”
Raph didn’t answer. He just nudged her toward the edge of the bed and stood up, rolling his shoulders like he’d been sleeping in an awkward position all night.
“C’mon,” he said, jerking his head toward the door. “Let’s go.”
Leo was so confused.
But she climbed out of bed anyway, her body moving on autopilot as she followed Raph into the kitchen.
The smell of breakfast hit her nose first. Then, the sound of clinking pans. Then—
“Good morning, sweet pea!”
Leo barely had time to process Mikey’s greeting before she felt something off . The tone of Mikey’s voice—
It was softer. Brighter. Almost… cooing .
Leo squinted.
She glanced toward the kitchen island, where Mikey was flipping pancakes. Donnie sat nearby, hunched over a steaming pot of coffee, sipping directly from it like a goblin.
Leo’s confusion only deepened.
She had no idea what was going on.
Mikey turned around, smiling at her like she was the cutest thing he’d ever seen .
“Did ya sleep good, baby?”
Leo froze .
Her brain skidded to a stop .
“What?!”
Mikey blinked. “What?”
Leo’s face scrunched in confusion. “Why are you—what— baby ?”
Raph sighed, rubbing his temples. “Yeah, okay, she’s definitely big again.”
Mikey gasped .
Donnie, who had been sipping their coffee with a dead expression, finally looked up, eyes flicking over Leo with renewed focus.
“Oh,” they muttered. “You’re back.”
Leo’s eye twitched. “WHY DOES EVERYONE KEEP SAYING THAT?!”
Raph huffed, jerking a thumb at Donnie. “Go ahead, genius. You explain.”
Donnie sighed, setting down their coffee pot reluctantly.
“Okay,” they started. “So, uh… Leo? Last night, you regressed.”
Leo blinked.
“…Regressed?”
Donnie nodded. “Age regression. It’s a PTSD response—basically, your brain slipped into a younger state to cope with stress.”
Leo’s stomach dropped.
“I—” Her voice faltered. She shook her head. “No. I wouldn’t —”
Raph snorted. “You did .”
Mikey grinned. “You were so tiny, Leo! It was adorable! ”
Leo’s blood ran cold.
Her hands curled into fists at her sides. “No.”
Mikey nodded eagerly. “Yes! You—”
“ No! ” Leo said, louder this time.
Her voice shook slightly.
Mikey’s grin faltered.
Leo swallowed, shifting uncomfortably under their stares. “It—it won’t happen again,” she said quickly, shaking her head. “I—I'm sorry. I didn’t—”
Donnie’s brow furrowed. “Leo, you don’t have to apologize.”
“Yes, I do ,” Leo snapped. “I—I don’t even remember it! I—I acted like a baby , and I—”
Mikey suddenly stepped in.
“Leo.”
Leo shut up.
Mikey softened. “We don’t mind,” she said gently. “You don’t need to be embarrassed.”
Leo felt her stomach churn. “But—”
Mikey shook her head. “No ‘buts.’ We’re family. If this is how your brain needs to cope, then we’re gonna be here for you.”
Raph grunted in agreement, crossing his arms. “Yeah, no shame in it.”
Donnie nodded. “We’d rather you cope in healthy ways, Leo. If regression helps, then it’s not a bad thing.”
Leo bit her lip. She wasn’t convinced. She still felt mortified .
Her brain had shut down , made her small , made her cling to Raph like a helpless child.
That wasn’t her. That couldn’t be her.
Mikey suddenly looped an arm around her, pulling her into a side hug. “I get it, Leo,” she said. “It probably feels weird. But I promise, we don’t care. We loved baby Lee.”
Leo groaned, pressing her hands into her face. “Please stop talking.”
Mikey ignored her entirely.
“You were so cute,” she continued. “You called Raph Raphie , and you snuggled him like a teddy bear—”
“Mikey—”
“—You got so excited about apple juice—”
“Oh my God —”
“—And you wouldn’t let anyone but Raph tuck you in—”
Leo was dying .
Raph smirked. “She really wouldn’t.”
Mikey grinned. “And she had a tantrum when I tried!”
Leo groaned again, dragging her hands down her face.
“ Please shut up,” she begged.
Mikey cackled.
Donnie just sipped their coffee. “We did make a list of things to get in case it happens again.”
Leo’s eye twitched. “What.”
Mikey nodded. “Yep! Raph even agreed to getting you a sippy cup.”
Raph’s eyes widened. “I did not! ”
Donnie pulled up their phone. “You literally did.”
Raph pointed at them. “I agreed to snacks, not sippy cups!”
Leo felt her soul leave her body .
Mikey beamed . “It’s okay, Raphie. We’ll find one with dinosaurs on it.”
Raph shoved Mikey off her stool.
Leo collapsed onto the counter, hiding her face.
She wanted to disappear .
Donnie just sighed, sipping their coffee again.
“Welcome back, Leo.”
Leo had decided she was going to pretend none of this ever happened.
She was going to push it so deep into the back of her mind that it would become a distant, hazy memory, never to be acknowledged again.
Unfortunately, she had three annoying siblings who refused to let that happen.
~~~~~~~~~~
The rest of breakfast had been painful .
Not because anyone was making fun of her—no, that would have been easier . Instead, her siblings kept looking at her like she was some delicate little flower that needed reassurance every five minutes.
Mikey kept sneaking her little smiles. Raph kept watching her like she was gonna shatter. Donnie kept giving her that stupid patient look that meant they were waiting for her to accept something she didn’t want to accept.
It was infuriating .
She didn’t need them to coddle her. She was fine .
The regression thing? It was a fluke . It wouldn’t happen again.
She didn’t need it.
Right?
She kept to herself most of the morning, disappearing into the dojo under the excuse of training. She ran through drills, practiced katas, stretched her muscles—did everything she could to feel normal .
But something wasn’t sitting right.
Her body felt off . Heavy.
Like she was still waking up.
Like something in her brain hadn’t fully settled yet.
She scowled, tightening her grip on her swords.
It won’t happen again.
But what if it did ?
Leo’s hands clenched.
Would she even know it was happening?
She still barely remembered last night—just flashes of warmth, of apple juice, of Raph’s voice rumbling in his chest when she leaned on him.
She hated how nice that sounded.
She hated how safe it made her feel.
She—
“Leo!”
She jumped, whipping around—only to see Mikey grinning at her from the doorway.
“Dude,” Mikey laughed, stepping inside. “I called your name like, three times.”
Leo forced herself to relax. “Sorry. Just thinking.”
Mikey hummed, rocking on her heels. “Whatcha thinkin’ about?”
“Nothing,” Leo lied.
Mikey snorted. “Uh-huh. Sure. ”
Leo sighed, sheathing her swords. “Did you need something?”
Mikey perked up. “Yeah! We’re gonna watch a movie—wanna join?”
Leo hesitated. “What movie?”
Mikey wiggled her eyebrows. “ Space Heroes: The Final Battle. ”
Leo almost groaned out loud.
She loved that movie.
Mikey knew she loved that movie.
She shot her sister a look. “You planned this, didn’t you?”
Mikey gasped dramatically. “How dare you accuse me of such tactics!”
Leo rolled her eyes.
Mikey just grinned. “C’mon, Leo. Let yourself chill for a bit.”
Leo frowned. “I am chill.”
Mikey raised an eyebrow.
Leo crossed her arms.
Mikey tilted her head. “You literally haven’t sat still all day.”
Leo opened her mouth—then closed it again.
Mikey just smirked, holding out a hand.
“C’mon, big sis,” she said. “Let us take care of you for a little while.”
Leo hesitated.
She didn’t need taking care of.
She didn’t need—
But then she thought about last night.
About how easy it had been to just… exist.
No worries. No responsibilities. No expectations.
She swallowed.
Then, slowly, she took Mikey’s hand.
Leo did not expect to end up snuggled between Raph and Mikey on the couch.
She did not expect a fuzzy blanket to get draped over her shoulders.
She did not expect a steaming mug of hot chocolate to be shoved into her hands.
She did not expect Donnie to settle on the armrest beside her and rub her back .
And worst of all?
She liked it .
It wasn’t just cozy .
It wasn’t just warm .
It felt… safe .
She scowled into her hot chocolate, barely paying attention to the movie.
Raph, who had been casually watching her sulk for the past ten minutes, finally sighed.
“Alright, spill,” he muttered. “What’s eatin’ you?”
Leo shook her head. “Nothing.”
Raph narrowed his eyes. “Leo.”
Leo exhaled, sinking further into the blanket. “I just… don’t get it,” she admitted.
Mikey tilted her head. “Get what?”
Leo hesitated.
Then, quietly—“Why you guys are okay with this.”
The room went silent.
Leo felt her face heat up.
“I mean,” she continued, forcing herself to talk, “it’s weird , right? I just— turned into a baby out of nowhere! That’s not… normal .”
She looked down at her lap, gripping the mug tightly. “Shouldn’t you guys think it’s weird ?”
Raph sighed.
Then, suddenly, he reached over and flicked her forehead.
Leo yelped, jerking back. “Ow! What the hell?!”
Raph smirked. “You are weird, Leo. We all are.”
Leo scowled. “That’s not the same.”
“Sure it is,” Raph shrugged. “You think I chose to have anger issues? Or that Donnie wants to be a compulsive perfectionist?”
Donnie hummed. “He’s not wrong.”
Leo frowned.
Mikey leaned in, nudging her shoulder. “Leo, we all have our baggage. We all deal with it differently. This is just… your way.”
Leo chewed on her lip.
Donnie finally spoke, voice calm and patient.
“Leo,” they said, “Your brain needed this. You’ve been running on fumes for years . If this is how your mind keeps you from burning out completely… then it’s not bad.”
Leo’s hands tightened around her mug.
She still wasn’t sure. She still felt off about it. But…
She looked around the room.
At Mikey, smiling softly, eyes filled with nothing but warmth.
At Donnie, watching her carefully, their expression calm and understanding.
At Raph, who had always been her rock, who was sitting beside her, arm draped across the back of the couch, completely at ease.
They weren’t looking at her like she was broken .
They weren’t looking at her like she was weak .
They were just… there .
Leo exhaled.
“…Okay,” she murmured.
Mikey perked up. “Okay?”
Leo nodded, just barely. “Okay.”
Mikey grinned. “That’s my big sis.”
Leo rolled her eyes. But she didn’t pull away when Mikey hugged her. She didn’t move when Donnie rubbed slow circles into her back. And when Raph tightened the blanket around her shoulders, keeping her warm and safe—
She let him.
Maybe, just maybe …
This wasn’t so bad.