It's early spring and something is horribly wrong.

After eighteen years, Destiny likes to believe that she knows everything about her body. She knows when her aches and pains are from sleeping funny or when it's from the previous day's training. She knows when her bad mood comes from a crappy night of sleep or when it's almost time for mother nature's monthly visit. She knows herself, better than she knows anyone.

Something is wrong and she can't explain it away this time. These symptoms are new to her.

She's irritated, fidgety, and her senses feel like they've been kicked into overdrive. She's hyperaware of every movement her body makes, of the scents coming off her fellow lair-mates, and she has urges: horrible, painful urges that make her feel like she's a second away from devolving into a wolf and staying that way.

She has theories, but none of those theories ever stick around because whenever she thinks of them, the object of her irritation arrives.

It's all because of Leonardo.

She's known his scent for as long as she's known him. Incense, fresh air, always the nicest smelling of the turtle brothers because he's the only one unafraid of personal hygiene. To be fair, the others are fine, but Donatello has a habit of locking himself in the lab for days on end, Raphael insists that there is nothing wrong with his "natural musk" and Destiny is pretty sure that Michelangelo only discovered deodorant because of Annalise.

Leonardo's scent is stronger now, muskier, and it invades her senses anytime he comes near her. It goes straight to her brain, spreading through her body and making her feel hot inside. That heat lingers long after he's gone, follows her to her bedroom and reignites when she smells his presence on her pillow, on her blankets. It drives her loopy to the point that if he so much as tries to touch her, she wants to bite his hand off. At the same time, she wants him to come closer, touch her more. The dissonance does nothing to help.

She assumes she's being extra hormonal because her period is coming, despite all her common sense telling her that it's never been this bad before, but after two days of torture, she breaks. She goes to the laboratory the first chance she gets, slamming the door behind her and making Donatello and Sarina jolt up from their work. Metalhead II beeps in surprise.

"I think I'm sick," she says.

Sarina's eyes flash. "Ah, is this the supposed fever you mentioned?" she asks.

"Yes? Maybe?" Destiny growls under her breath, digging her fingers against her scalp. "God, I...I don't know, but something's wrong!"

Donatello's eyes widen a little. "Oh, and...do you think this has to do with how you've been snapping at Leo when he gets near you?"

"That too."

Donatello and Sarina exchange a glance. Donatello groans and covers his face with his hands as Sarina exhales, her eyes flashing again. Destiny frowns and storms closer to them, fists quivering at her sides.

"You know something," she says, keeping her voice low. "What is it?"

"I...so did not want to have this talk with you," Donatello mutters into his hands.

Sarina smiles apologetically at Destiny. "Please understand, we've noticed your...condition. We couldn't help but look into it."

"Would you tell me what it is already?" Destiny snaps, her tail spiking up as she bares her teeth.

Donatello slowly lowers his hands. "Okay, okay, please calm down," he says. He sucks in a breath. "I, ah...guess I'll keep this short and sweet, but it's highly likely that you're in heat."

You could have heard a pin drop. Metalhead makes a long, droning beep and looks away, antennae twitching. Sarina purses her lips and Donatello doesn't look Destiny in the eye.

"I'm...what?" she repeats. "That...that's never happened before! Wouldn't it just be because of my—"

"We thought the same thing," Sarina cuts in. "Here's the thing, you have recently reached physical maturity. Technically, humans stop ageing around twenty-five, but eighteen is still maturity. Our theory," she says, gesturing to Donatello and making him shrink further into himself, "is that your mutation is causing some kind of secondary puberty."

Destiny gapes at her for a second before crossing her arms tightly over her chest. "I...that..." She shakes her head. "I'm having freaking wolf puberty?!"

"Basically," Sarina says. "Lately, I have been exploring how mutations change the body, mostly because of you. I have many theories about how your raven DNA could affect—"

"No, no," Destiny interrupts. "I don't want to hear anything else. Not yet. Please." She exhales, windmilling her hand. "So, so...what do I do? How long is this stupid...heat...going to last? If it's even heat."

"It's most probable that it is. Female wolves go into heat around this time of year. Ah, searching for a mate and all," Donatello says, finally unfurling himself from his ball of shame. "It usually lasts for five to seven days. With time, we could develop a suppressant to help you in the future. For now, you...ah...have two options."

Destiny gives him a withering, long-suffering glare. Donatello looks at Sarina, begging her silently, but she stays quiet. Her expression is expectant, patient, and Donatello groans into his hand before inhaling sharply.

"You can wait it out or find a way to relieve yourself," he grits out.

Destiny turns completely red and her overheated body somehow rises even further in temperature. "Huh?!"

"He is suggesting that you engage in coitus," Sarina pipes up.

"YEAH, NO SHIT, SARINA!" Destiny roars. The cyborg leans back, eyes wide with alarm, and Donatello crumples against his desk with a whimper. Destiny turns away. "Nope. No. I'm going to wait this out."

Sarina blinks. "Oh, I'm sorry," she says. "I assumed that it was something familiar to you. You and Leonardo are very physically affectionate—"

Just the sound of his name sends Destiny's brain spinning, filling her head with images, and she grips her ears. "We've only been together again for a little while!" she says, voice rising in pitch. "T-This...gah...no, no. I can't. Thanks for your help, but I'm going to wait. Thanks!"

She races out of the lab, the door closing behind her sharply, and Sarina takes a second to blink and breathe before she swivels her chair towards Donatello. He stays sitting with his face down on the tabletop, a sustained groan just audible.

"Please do let me know if you ever experience heat," she says. "I will gladly assist you."

Donatello goes boneless with a shocked squeaking noise, sliding off his chair and collapsing to the floor. Sarina blinks at him in surprise.

"Was that too forward?"

----------

"Donnie? Sarina?" Leonardo calls, slowly pulling the door to the lab open. "You in here?"

"Hello, Leonardo," Sarina greets with a smile. "Is everything alright?"

He sighs, rubbing his arm absentmindedly as he wanders closer to them. "I mean, I want to say yes, but it isn't," he says. "Destiny's being—"

"Oh, shell," Donatello mumbles. Sarina stifles a laugh, pressing her fingers to her lips.

Leonardo blinks, mouth half-open. "Um, is..." He looks at Sarina, then back at Donatello. "What?"

"Nothing," Donatello says. "Continue."

"Oh...kay." He clears his throat. "So, Destiny's being really..." He exhales, flapping his lips, searching for a word until he says, "Okay, don't tell her I said this, but feral." Sarina snorts, shifting her entire hand to cover her mouth, and Leonardo glares at her. "Yeah, I said it. But, yeah, basically I'm getting really weird vibes from her and I want to help but she won't let me."

"She's...going through some things," Donatello says, still looking far too tired for any of this. "You should ask her about it, okay?"

"So you do know what's wrong," Leonardo says.

"We do, but this is not something we should spread around. It's very private for Destiny and if you really must know, I agree that you should ask her," Sarina says.

Leonardo's face falls. "She...she's not in trouble, is she? Did I do something?"

"No," Donatello says. "You didn't do anything wrong." He looks up at him. "As your brother, who you supposedly love, I am begging you to just...ask her. I really don't want to discuss this with you."

"Supposedly?"

"Here's an idea!" Sarina says, getting to her feet. She places her hands on Leonardo's shoulders. "Why not take Destiny on a date? Take her out to someplace nice, make her feel special, and talk. I promise, all will be well."

Leonardo eyes her for a second before he sighs. "Alright. Thanks for...the help."

"We didn't help," Donatello says. "No need to thank us."

Leonardo doesn't argue, stepping away from Sarina, turning on his heel, and leaving the lab. Sarina exhales, sinking back into her seat, and again looks at her boyfriend.

"Thank you for keeping quiet about it," he says.

"Of course. It is not my business to share," she replies. Her lips pucker, brows furrowing. "Although, I don't see why you have to be so awkward about this. It's only natural."

"That's true, but it's also...intimate, Sari." He shakes his head. "I'm sorry, I just...it's not something I completely understand outside of books and medical journals."

Her eyes flash. "If you ever want to change that—"

"A-Ah!" He waves his hands at her. "I...uh..." He coughs, his face completely red. "You...have...said that before. Thank you."

Her shoulders sink, head bowing. "Are you...disgusted by the idea of doing such a thing with me?"

"No!" he says, a little too loud. He scoots closer, taking her hands. "I...I very much like that idea, but I'm..." He bows his head, lightly thumbing her knuckles. "I have a lot of insecurities, mostly about our physical compatibility. I just don't want to disappoint you."

"Oh, Donatello," she sighs. She brings herself closer, leaning in to press a gentle kiss to the corner of his mouth. "I apologize," she says, pulling away. "I didn't mean to pressure you. I will remain silent on the matter unless you bring it up first, alright? We must communicate about these things."

He gazes at her, still holding her hands, and he smiles. "I love you," he says.

She returns his smile. "And I love you."