Casey thought that a good night's sleep would help, but he feels like shit when he wakes up. He had one too many nightmares, a horrible mash-up of all his usual night terrors, and yet even now he can barely recall anything other than how they made him feel.

Cheerful chatter comes from the kitchen as Casey hauls himself off the couch and stumbles off to the kitchen, yawning into his hand. He windmills his arm a little bit, frowning at the ache that seems to spread down across his collarbone and pectoral. He must have slept on it funny.

Inside the kitchen, the Hamatos crowd around the table in high spirits. Raphael and Leonardo chuck cubes of cheese across the table at each other, trying to catch them in their mouths while Donatello and Sarina nurse their coffee in matching mugs (his has Charles Darwin on it, hers has Marie Curie). Destiny and Michelangelo work by the stove, with Destiny mixing eggs and chopped ingredients into bowls while Michelangelo turns the mixtures into the fluffiest, most perfect omelettes that Casey has ever seen.

"Morning sleepyhead," Destiny calls as Casey enters. "What'll it be?"

"You can have-a anything-a you want-a at Chez Mikey!" Michelangelo says, making vaguely Italian hand gestures.

Casey settles into a chair, flexing his hand in an attempt to get rid of the tingling feeling spidering down his chest. "Meat, and lots of it," he says. A sharp pain shoots through his left pectoral and he hisses, pressing his hand to the spot.

"You okay, man?" Raphael asks. Leonardo accidentally hits him in the eye with a cheese cube. "Ow! Watch it, Leo!"

"Sorry! Sorry..." Leonardo says, holding his hands up.

"I'm fine. Just tired." Casey's vision swims and he squints as a headache builds against his forehead. His concussion symptoms must be acting up. He plunks his head on the table with a groan.

"One meaty omelette, coming right up!" Michelangelo calls. "Fully hyping myself up; these might be the best omelettes ever."

"Are you sure you're okay, Casey?" Donatello asks. "Didn't Zilla take care of that bite wound?"

"She got rid of the shade. It still hurts like a bitch," Casey grumbles. It's itchy, too, and at the thought he scratches at the bandage.

"My, someone is testy this morning," Sarina quips, taking a sip of her coffee.

Casey lets out a sarcastic laugh in response. He had a crummy sleep and he fell off a building three days ago. Once he gets some food and coffee in him, he'll perk up and it'll all be fine. He's surprised that Annalise isn't around, until he remembers her mention of school yesterday, and a sick feeling curls in his gut. He already has so little responsibilities outside of passing math, and here he is skipping school.

Damn it. Maybe he can call out sick. He sure feels like it.

There's the soft clink of ceramic against the tabletop as Destiny sets a steaming omelette in front of him. It smells amazing, but as Casey sits up and takes the fork from her, his stomach churns all over again.

He flinches away from Destiny's touch as she brushes his bangs away from his forehead. She frowns at him as she presses her palm to his forehead. Her nostrils flare, ears pulling back.

"You feel pretty hot, Case," she says. "And you don't smell too good either."

He brushes her hand away. "I'm just not feeling good, wolfie. Let me eat," he mutters. He stabs the omelette, tearing off a chunk and shoving it into his cheek.

Destiny frowns deeper, but she backs off, eyeing him all the way back to the omelette station. Casey keeps shovelling omelette into his mouth. It settles his stomach, but it does nothing for the chills spreading from his shoulder downwards. His heart feels like it's throbbing and not in a normal way.

"What do you mean, he doesn't smell good?" Leonardo asks.

"I mean he smells like...rot," she says. "Acrid."

"Like infection?" Sarina asks.

Destiny's ears flatten and she approaches Casey again. "Let me see that bite."

"Can it wait? I'm not dying," he whines as he keeps eating. "Bandages probably need changing anyway." What happened to letting someone feel like shit?

"Don't get snippy with me. We aren't screwing around when it comes to shade," Destiny retorts. He gives her a tired glare and she sighs. "Fine, but as soon as breakfast is done, we're cleaning that wound."

"Yes, ma'am," Casey drones.

At least the omelette is delicious.

----------

After Casey goes to the bathroom and splashes water on his face, he makes a stop by Donatello and Sarina's laboratory. They're already inside, armed with fresh cups of coffee. The mutant-hunter guns lay out on their work table, some already partially disassembled.

"Casey!" Donatello greets as he enters. "Let's take a look at that bite."

"Before that," Casey says, holding his pointer finger up. "I've gotta ask you guys...what are the chances that you could make a retro-mutagen for Zilla?"

The mutants share a look, once again speaking their own silent language, and between his headache and worsening body aches, Casey doesn't have the time or patience for them to be doing what they do.

"Oh, come on," he says. "You guys are always looking for a new challenge."

"It is not the challenge we worry about," Sarina says, pursing her lips. "Zilla's situation is wholly unique to her. Even the shadow beasts had some sense of solidity to them, but her?"

"Creating retro-mutagen takes intense trial and error," Donatello adds. "We barely have any inanimation mutagen left from the garage and if we ruin it, that's it."

"We would have to start from scratch using regular mutagen, then try to recreate inanimation mutagen, and then try to retroactivate it," Sarina continues. "The more I think about it, the more impossible it gets."

"What, you guys can't get more mutagen?" Casey asks.

"It's already a finite resource since the Kraang disappeared, and we need to use what we do have to make human patches," Donatello says.

"You guys lived without those patches for years!"

Donatello stands from his seat, brow furrowing. He takes a breath, expression smoothing as he calms himself. He speaks evenly. "We can look into it, but I'm telling you, I don't see this going well. There are too many factors and too little materials to guarantee any kind of success."

Casey breathes hard, frustration making his heart race enough that it starts to hurt. His hands clench into tight, shaking fists. They won't even try? Why won't they try? Doesn't Zilla deserve to live a normal life after everything she's been through?

Donatello's face softens. "I'm sorry, Casey. I wish I could help her. We both do." He gestures back to Sarina, who nods in emphatic agreement.

His eyes screw shut as another wave of chest pain racks his body. He tries to speak, but his words choke him. The world starts to tilt and he realizes that he can't breathe.

He hears the lab doors slide open behind him. "There you are!" Destiny says. "Don, Sarina, did you look at his—"

Casey's knees buckle. He hears Donatello and Sarina shout as he falls into someone's arms. Destiny appears above him, eyes wide as she lowers him to the floor.

"Casey? Casey, talk to us," she demands.

His vision scissors and he manages to suck in a breath, but the chest pain has grown so bad that it feels like a chore. He's faintly aware of more shouting and rushing footsteps before Raphael, Leonardo, and Michelangelo are there too, faces bobbing in and out of his view.

His ears ring and a single, confused, foggy thought comes to mind. Zilla took care of it. He's fine. He should be fine, he thinks as, for the second time in less than twenty-four hours, his vision goes black.

----------

"What happened?" Leonardo demands as Casey goes limp in Destiny's arms.

"I don't know!" Destiny says, a rare pinch of panic in her voice.

"He was asking us about retro-mutagen and he just...collapsed," Donatello says as he kneels next to Casey, tugging his eye open and shining a light into it. "Well, his pupils are—"

Casey jerks away from the light as he sucks in another laboured breath. The movement draws everyone closer to him, panic and confusion reflected in every expression.

"H-Hurts—" Casey gets out.

"What hurts?" Raphael demands. "The bite?"

Casey arm jerks, just managing to motion to his chest. Destiny's hands flit to his shirt, her finger catching on a small hole in his sweater. She frowns, tugging the fabric aside, and her brow furrows and her nostrils flare again.

"Oh, fuck," she mumbles. "Casey, I thought the buck bit you!"

"He did!" Raphael insists. "Zilla took care of it right away."

"Des, what is it?" Leonardo asks, shockingly calm, betraying nothing.

"I knew I smelled something wrong," she says. She glares at Casey even as her mouth trembles. "You idiot, why didn't you let me look at the bite?" Casey doesn't react to her words, eyelids twitching, chest quivering with every strained breath. "We need to get his shirt off."

Raphael and Michelangelo sit Casey up for long enough to pull off his shirt, revealing a puncture wound in his chest just below his collarbone. The makeshift bandage around Casey's shoulder appears fine, stained faintly red, but the puncture wound is deep and purpled, festering with black pus and sickly purple veins stretching out across his left pectoral and underneath the bandage.

Destiny covers her nose, ears tucking back as she suppresses a gag.

"The hell?" Raphael gawks.

"I'm getting Splinter," Leonardo says, hurrying from the lab in the next breath.

"The buck," Destiny says. "It had antlers. It must have stabbed him during the struggle." She shakes Casey, rattling him from his near unconsciousness. "Why didn't you say anything?"

"I...didn't know," he gets out. He coughs and the wound seems to pulse, spitting out more dark pus. His eyes start to droop again. "The bite...I went numb. Didn't...realize."

"He's not shaded, right?" Michelangelo asks, looking back at Donatello and Sarina. "Right?" Sarina's lips part. She stares at the wound, then snaps her mouth shut again. Michelangelo's expression falls. "Oh...oh, no."

Donatello unwraps the bandage to examine the bite. It's not shaded, not like the puncture wound festering in Casey's chest, but it's not good either. The skin looks red, irritated.

"What do we do?" Destiny asks. "Could we get Zilla?"

"We'll need to get a hold of her," Donatello says, "but I don't know what she could do. This wound is affecting Casey far differently than Raph's. Sarina, what do you think?" He looks back at her, at her slack expression, and he repeats, forcefully, "Sarina!"

She blinks, startling. "I...it..." She clears her throat and her eyes flash rapidly. "It seems that due to our exhaustion yesterday, we neglected to clean and disinfect the injury like we did for Raphael. The presentation of symptoms suggests something akin to rabies, with light aversion rather than water. There is a chance the shade has spread faster due to the depth—if it has punctured anything vital, even nicked it, then—"

"We don't have time for this!" Raphael snaps. "He needs a hospital and he needs it fast! We—"

"Everyone, take a breath," Splinter says as he arrives with Leonardo on his heels. "We must remain calm if we are to help Casey." He looks down at the young man and the wounds and his eyes widen. "Such a small thing and yet it causes so much pain."

"Get him ready for transport," Leonardo says. "Donnie, Sarina, we need human patches. Raph, Mikey, call Andy and Annalise. Taylor, too." He pauses as he lets out a sigh. "Actually, Donnie, maybe you should call April."

"You sure?" Donatello asks, eyes widening a bit.

"She'd want to know. Do it."

They race off to fulfill their tasks, leaving Destiny, Leonardo, and Splinter with Casey. Splinter kneels next to the boy, lightly hovering his hand over his chest as his large ears tuck back in distress.

"I do not understand," he murmurs. "Raphael's wound was not like this."

"None of us knew about it," Leonardo says. "Maybe, if we could've cleaned it, looked after it better, maybe—"

"There is no time for the maybes now, Leonardo," Splinter says. "Mistakes happen. All we can do now is hope to remedy it." He takes a deep breath. "It is a good thing the beasts are gone, if they can cause harm such as this."