Donatello waits with bated breath as he watches the cells underneath the microscope. It's yet another sample from Timothy, but this batch holds what could very well be his last hope for returning to normal.

Donatello has worked tirelessly with Sarina on their projects, as they always do, but the run-in with the Italian mob may end up being Timothy's saving grace. Thanks to the mutant hunter rockets they retrieved from the Hammer's mech suit (now stripped for parts to be used in new projects, of course), they were able to study the concoction that they had cooked up. After all, there had to be something special in the nerve gas if it only targeted mutants.

Sure enough, they found that the chemicals were uniquely attracted to mutant DNA and, with some of the magic of science, Donatello and Sarina were able to isolate the factor that attacked mutant cells and reverse engineer it. Basically, they used something meant to harm mutants to help them, and now they're hoping that this specialized dose of retromutagen will revert Timothy back to his human self.

Donatello bites his lip nervously. They used every bit of gas for this and, if this dose is a failure, it's back to the drawing board.

But, before his eyes, the mutagenic cells warp, twist, and revert back to normal. His eyes widen and he sits back, looking back at Sarina to find that she's already waiting with a clipboard in hand.

"I...I think we did it," he says, breathless.

Her eyes flash. "It worked?"

He nods, stumbling to his feet as he starts to laugh. "It worked! Oh, baby, it works!"

He scoops her into a hug as she lets out a cheer, the both of them laughing and stealing hasty kisses as they celebrate. Donatello sets her down, holding up his hands as he waves them.

"Wait, wait wait wait," he says. "We should save the celebrating for after. Don't want to count our chickens before they hatch."

He picks up the retromutagen vial on the table, now tinged a slightly more blood orange colour than usual. It's warm to the touch. He moves to the frozen tank and stops in front of it. The tank has become a staple piece in his lab and, until this moment, Donatello wondered if it always would be. Timothy's bulbous, glassy eyes stare out at nothing and Donatello rests his hand on the frosty glass.

"Alright, buddy, moment of truth."

He opens up the hatch at the top of Timothy's jar that he used to feed him through, but hesitates as he grips the vial.

A gentle hand touches his shoulder as Sarina steps to his side. "Nervous?" she asks.

Donatello swallows. "The last time we spoke..."

He shakes his head, but he can still picture it so clearly—Timothy on a rampage, desperate to befriend April but doing it the wrong way. That was shortly after Casey came into April's life, and then theirs, and Donatello cringes to think of how he acted back then. There are a lot of things he would change if he could go back, a lot of words he wouldn't say.

He's still afraid of what Timothy may feel, and what may have happened to him while he was frozen.

"Moment of truth," Donatello repeats, half to himself.

He tips the vial into the hatch, then closes it. He steps back, Sarina close behind, and they watch as the mixture floods over the icy blob of organs and goo. For a second, nothing happens. Then, the ice starts to melt, slowly, then rapidly, and colour starts to bloom from Timothy's frozen heart. It pumps once, twice, then more.

"Donatello," Sarina says.

Donatello nods, gawking at the sight before him. "Yeah?"

"Don't you think we should have tried to remove the jar before carrying on?"

He blinks. "Oh. Right. Shell."

Sarina moves closer to the glass, but things are starting to swirl. The green colour of the slime in Timothy's body becomes opaque as the organs disappear from view, jiggling and twitching as the jar shakes, and Sarina presses her hand to the glass. It's warm, getting warmer, and she can feel the vibrations of a frantically beating heart from somewhere inside.

"Donatello, stand back!" she shouts.

He disappears into his shell just as she aims her open hand at the glass and fires off a blast. It cracks and, after another second, shatters.

Sarina leaps back as a mix of water and sludge spills from the jar and, carrying with it, the curled and naked body of a teenage boy. He lands on the laboratory floor with a wet slap as the wave crashes down, spreading across the floor, and things fall silent.

Donatello pops out of his shell as Sarina moves to the boy. His eyes are closed, his black hair sticking to his face, and when Sarina touches his shoulder, he's feverish beneath the wetness clinging to him.

"Timothy?" she calls, rolling him onto his back and tapping his cheek. "Timothy, can you hear me?"

He lets out a small groan and his eyes peel open. He blinks, pupils dilating and focusing for a few seconds.

"Who...?" he starts, his voice creaky with disuse. "Where...am I?"

Donatello approaches with a blanket, covering him up as he kneels beside him. "Timothy, it's Donatello," he says gently. "Are you okay?"

Sarina helps Timothy sit up, tucking the blanket around him as they go. Timothy keeps looking around, dazed, and Donatello settles in front of him, waving a hand in front of his eyes.

"Tim?" he asks.

Timothy takes a big, deep breath, then tugs the blanket closer. "Donnie? I...I don't understand. Last thing I remember, I was grabbing some mutagen, and..." He looks down at himself. "I'm...not goo anymore, and you..." He tilts his head, leaning closer to Donatello. "Are you older? You look older."

"Metalhead?" Sarina calls. The robot beeps as he stirs from standby mode, and she motions for him. "Analyze."

Timothy shrinks away from the metal turtle as he comes closer, antennae swivelling. He straightens, beeps, and turns to Sarina. She closes her eyes as a soft whirring noise comes from her. Then, she gasps, and her eyes snap open as they flash. Timothy gawks at her.

"He hasn't aged," Sarina murmurs. Her eyes flash again. "Donatello, he hasn't aged."

Timothy keeps staring, eyes wide. "Uh, hey...robot...lady?"

"Sarina," she corrects. "I am Donatello's partner. We worked together to change you back. Metalhead just scanned your body and sent the data over to me. From what he found, you don't seem much older than sixteen."

"Because I am sixteen," he says, brows still furrowed with confusion. "Huh, wait, how long was I out? It doesn't feel like that long."

Donatello shares a brief look with Sarina and she purses her lips, but nods and gestures to him. Donatello exhales, folding his legs beneath him in front of Timothy.

"It's a long story," he says, "but I'll explain it the best I can."

----------

He doesn't take it well, but he also doesn't have a meltdown, and Donatello is honestly grateful for that. The Timothy he barely knew years ago was arrogant, impatient, bull-headed, and he was a stupid teenager who wanted to be a hero. He trusted the wrong people.

Timothy passes out shortly after they finish explaining things and, with some help from Metalhead II, they make him comfortable on the lab's exam table. He sleeps for hours under constant monitoring from both Sarina and Metalhead, watching and waiting while Donatello tells his family the news and consequently fends them off from rushing into the lab and staring at Timothy like he's a zoo animal. He locks up the lab, then gets to work mopping up the slime and water mixture from the floor.

Hours pass. Timothy's fever goes down steadily and his vitals stabilize. He shows no sign of changing back to his goo form and, when he wakes again, far calmer and feeling better, he only has one request.

"Could you take me home?"

Donatello and Sarina drive the Party Wagon down the quiet streets in silence. In the back, Timothy keeps mumbling to himself, talking about his mom, about his best friend, about what's happened since he froze. They were able to lend him one of Splinter's kimonos, as he's still quite a bit larger than any of the clothes the turtles keep around for when they use their human patches.

Timothy remembered his home address, there's just no way of knowing whether or not his mom is still there.

Donatello's GPS lets them know that it's just around the corner and, in a few short minutes, they're parked out in front of an apartment building. Timothy pokes his head through the opening separating the driver section from the back, and Donatello is struck by how different he looks when he's not wearing his Pulverizer costume. He's just a chubby-faced, freckled kid with big brown eyes and thick black hair.

"The light's on," he says, looking at the building.

"Perhaps we can check the window," Sarina suggests, pointing to the fire escape on the side of the building. "Would you prefer that?"

Timothy nods.

With some effort (Timothy admitted he felt a little weak in the legs), the three of them climb the fire escape up to the window belonging to Timothy's apartment. Timothy peeks inside, Donatello and Sarina watching over his shoulder.

They can't hear anything, but there's an aging Asian woman with a black bob cut sitting at a dinner table across from a young girl with medium brown skin and a mane of chocolate brown curls. Her eyes rival Destiny's in how bright and green they are. Timothy gasps at the sight of her.

"H-Hazel?" he whispers.

"Friend of yours?" Donatello asks.

Timothy nods. "My best friend." He leans closer to the glass. "She's...older. I mean, you said it's been a few years, but..."

He falls silent again, fidgeting despite the awed look on his face. Donatello and Sarina look at each other expectantly. Sarina pats Timothy's shoulder.

"Go ahead and knock," she says. "We'll be nearby."

The mutants disappear onto the roof, watching and waiting as Timothy squares his shoulders. He knocks on the window, just a few gentle taps, and someone answers after a few seconds.

Sarina and Donatello sit shoulder to shoulder, listening to the sounds of disbelief and surprise below them.

"Timmy? Is that really you?"

"Hi, mom. Yeah, it's me."

"Timothy! Holy crap, I...I can't believe it."

"Hey Hazelnut, you look...good."

"Oh, shush, this isn't about me. Look at you! Where have you been?! I looked everywhere!"

"You...you did?"

There are quiet sobs, mostly from Timothy's mom, and then the sound fades. Donatello pokes his head over to see that Timothy has disappeared. It seems no one wanted to wait for him to go in the proper way and just helped him through the window.

A burst of emotion grips Donatello's chest. He sniffles and blinks rapidly, startled at his own tears, and Sarina takes his hand in hers, bringing it to her chest as she leans closer.

"Oh, darling..."

"I just..." He laughs a bit and wipes his cheek with the back of his arm. "I never thought I'd be able to make it right." He turns to her, reaching out to brush his fingertips against her circuit-patterned cheek. "I couldn't have done it without you, Sarina."

"I'm sure you would have been able to handle it."

"No, I mean..." He pauses. "Well, yes, maybe, but what always stopped me in the past was the guilt. The fear that, even if I did change him back, things would be worse for him. I was too afraid to face what I'd done and...I don't think I ever would have been brave enough to do this without you."

Her eyes glow brighter for a second as they widen. "I was useful to you as an emotional support pillar, and not just as a lab partner?" He nods, smiling a little, and she lightly touches her chest. "That is so sweet of you, Donatello."

He presses a kiss to her cheek. "I mean every word, darling."

----------

They expect the lair to be quiet and dark when they return but, instead, Donatello and Sarina emerge from their lab to find the other three turtles, Destiny, and Splinter waiting in the living room, each holding a glass.

"Finally!" Michelangelo says, grinning. "We thought you'd never come back!"

"That's highly illogical," Donatello says. His younger brother keeps grinning and he sighs, smiling. "But, yeah, we're back. Timothy's home safe."

"What is all this?" Sarina asks, eyes flashing once as she looks at all of them. "Is there a patrol happening tonight after all?"

"No," Leonardo says. He straightens a little, lifting his chin and putting on a professional, serious air. "We wanted to celebrate you finally finding a retromutagen for the Pulverizer."

"It's about damn time," Raphael agrees, already sipping his drink. Destiny smacks him with her wing and he shoots her a glare as she points to his drink and shakes her head.

"To Donnie and Sari, for being smarter than all of us!" Michelangelo hoots, lifting his glass.

Splinter nods, swirling his drink gently. "It is certainly a milestone, a righting of wrongs. It shows maturity, Donatello."

"Aw, guys," Donatello says, rubbing the back of his neck. "You really didn't have to. Seriously."

"We're just glad we don't have to see him when we go into the lab. Gave me the creeps every time," Raphael says.

"Raph, come on," Destiny says.

"What? I can say that now. The kid's free and finally out of our hair."

"Who's gonna tell him that we're bald?" Michelangelo whispers to Leonardo, earning a smirk.

"I'll be the first to thank you all," Sarina says. "There's no need for further accolades, but I will take one of those drinks. What is it?"

"Sake," Destiny answers. "Splinter had a bottle stashed away."

"Are...we allowed to drink?" Donatello asks, eyeing his father hesitantly.

"It's Canada somewhere!" Destiny says with a grin.

Splinter chuckles. "I will allow it this time, as I'm here to supervise."

"In that case...I'll try it," Donatello says.

Splinter hands Donatello and Sarina a glass and, together, the family winds down the night discussing what happened with Timothy and what's on the docket for the pair next. After all, with the mutant hunter rockets disabled and a whole lot of parts to play around with, the possibilities are endless.

They discuss upgrading the Shellraiser and doing some maintenance on the Party Wagon. Michelangelo reminds them about the retromutagen dog biscuit that Donatello said was finished, but never got to Annalise after the Stockman fiasco, and Donatello promises to get that to her as soon as possible. Sarina assures Destiny that her hearing aids are still on the docket, only for Destiny to hand-wave it aside.

"I'm comfortable being a mutant, so take your time," she says.

As their glasses run low, the turtles recount what the Pulverizer was like so many years ago, before Destiny and Sarina came into their lives, and other tall tales. Eventually, everyone trickles off to bed. Donatello fully intends to walk Sarina to her room, kiss her goodnight, and retire to his own quarters, but tonight, she follows him, and he doesn't stop her.

Donatello yawns, untying his mask and hanging it on the hook next to his bed. It's been a few nights since he actually slept in his room, as he was so focused on his projects that he fell asleep in the lab more often than not. Today is a good day to get some real rest.

He flops onto his bed with a heavy sigh.

"Are you feeling alright, Donatello?" Sarina asks.

He yawns again, already nodding as he starts to sit up. "Yeah, just tired. It's been a long day."

"Understandable," she says, coming to the bedside and reaching down to gently caress his head. She tilts her head as she smiles at him. "You deserve the rest." He sighs, revelling in her touch as she presses a kiss to his forehead. "I'll leave you to sleep."

He grabs her hand before she can go, eyes locking. "Could you stay?" he asks.

Her eyes flash. "But you are going to bed."

"That's correct."

She lets out a small gasp. "Oh...I see, you're wanting a sleepover. Why didn't you say so?"

"Guess I didn't know how to say it?"

She climbs onto the bed, cuddling up to his side as she gazes up at him. "I'm happy to spend more time with you, Donatello, even if we're unconscious for most of it."

He shifts, rolling onto his side so that he can face her. She smiles softly at him, one arm folded beneath her head like an extra pillow, and once again, he's blown away that he has a woman like her at his side.

"Are you feeling okay?" he asks. "Is there anything on your mind?"

"There is always something on my mind," she quips. "Tonight, it's mostly centred around Timothy, future projects, and also how warm I feel from the sake. I wasn't sure how alcohol would affect me, considering my partial robotics." She pauses, eyeing him up and down. "Is something bothering you?"

"Why would it be?"

"You seem pensive, more so than usual, and troubled. Is there more going on that I can't see?"

He purses his lips. "Could I take you on a date tomorrow?"

Her eyes glow briefly. "Oo, should we go to the military junkyard? We could scrounge for parts, if you'd like."

"No, I mean a real date."

She frowns in confusion. "Do those dates not count?"

"No! Or, sort of." He flushes, clearing his throat. "I feel like I've been taking you for granted."

"I do not feel that way."

"Still," he insists. "You were surprised that I found you supportive as more than a lab partner, and now I'm thinking that I haven't been treating you like my girlfriend. All we do is hunker down in the lab and work on projects."

"I like working on projects!"

He feels himself sag as he gazes at her. Maybe he is overthinking this, but it doesn't stop the guilt from taking root in his chest. He reaches out, resting his hand on her hip, feeling the material of her jumpsuit beneath his palm.

"So...you don't want to go on a different kind of date with me?" he asks.

She shuffles a little closer to him, pressing her palm to his plastron. "I want you to know that I am perfectly content with the life we've built together so far," she says. He averts his eyes and she adds, "But a change of pace cannot hurt. I would love to go out with you."

"Really?" His expression lifts with hope. "You're sure?"

She giggles softly. "I was only trying to assure you that I was not unhappy," she says. "I did not mean to make you think I was uninterested in your date idea."

"Oh, good!" He laughs, a short "heh-heh-heh" as he grips her hip a little tighter. "I promise, we'll have an amazing time. I just have to do some brainstorming, maybe a flow chart, and—"

She cuts him off with a kiss, cupping his face as she pulls herself close, and he groans a little as he sinks into it. She teases his bottom lip with a swipe from her tongue, only to pull away when he gasps.

"I expect to be wined and dined, I should have you know," she murmurs. "Especially if you intend to make it special, even more if you feel you haven't been treating me like a girlfriend, hm?"

Calm down, Donatello, calm down, he tells himself, even though she's trailing her fingers up and down his chest and he's already thinking of somewhere else he'd really like her to touch.

"Yes," he chokes out.

Her lip curls mischievously, but she gets up, stretching a bit as she gives her short white hair a quick fluff. "Good. I'm quite excited," she says. "As for tonight, let's get some rest. Is it alright if I take my bra off? I'd rather not sleep in it."

Oh, if he could only turn off his imagination, and he can barely squeak out another affirmative before she's unzipping her jumpsuit and getting comfortable. He exhales, rolls over, and tries to focus on sleep.

He feels her climb back onto the bed, cuddling up to his shell and taking up the big spoon position as she lets out a happy sigh. She's warm and soft and he relaxes at her touch.

"I love you, Donatello," she murmurs. "Goodnight."

"Goodnight, my darling," he returns. "I love you too."

A/N: Hazel is an OC that belongs to VioletPixels! Thanks so much for letting me include her, Pix!