Sorry it has taken me so long to update! I really do have a ton of this story written – I've just not been ready to post more. Also, I moved, and my internet went bye-bye for far too long! I hope this chapter will make up for the absence!

I do not own the TMNT, Godzilla, or HEAT. I only kinda wish I did, but I'm not sure I'm really up to the challenge. I do wish these things were fully released on DVD, though!

Enjoy!

Don,

Thanks for the follow-up biological information – that clears up a lot of my questions. Except this one: how on earth did you manage to test yourself without a full laboratory? I believe your findings, of course, and they follow exactly from everything else you've provided me. I just can't fathom how you're getting the tools to do all this. If you're working from scratch, I'm impressed.

By the way, you haven't been tinkering in our system again, have you? Randy noticed we seemed to have picked up a hacker, and a persistent one. He's had to pull a bunch of our data off the network and we still can't find how deeply the attack penetrated. You're sure your encryption on these emails is sufficient? Maybe you'd better not send anything else for a while.

We also had a weird sort of visit from a guy in a black suit and dark glasses. Funny thing was that he introduced himself as an insurance agent, but I've had experience with people using that as cover for something else. Just a little too interested in Godzilla, and I think I saw him at one of our calls not long ago. Ever run into him?

Better go – the worms are calling!

Nick

-==OOO==-

Donatello had to smile as he finished reading the email from Dr. Nick Tatopoulos. Their exchanges had gone back and forth for a couple of weeks, and the turtle was delighted by what he found in Nick. Not only was the doctor highly intelligent, questioning, and flexible in his thinking, but he also had a sense of humor and practicality that set him apart from most of the admittedly dry scientific community. Already Donatello had gained new insights about their mutant DNA, and already his research had given Nick some new perspective on Godzilla.

Rereading the email, however, Donnie's eyes narrowed at the indication that the HEAT systems had been hacked, and at the description of Nick's visitor. The purple-clad turtle could only think of one individual who wore a dark suit and glasses, was obsessed with mutations, and would give Nick enough of a creepy vibe to even pose the question, and the answer was not comforting. Normally, Donatello would have taken this information straight to his brothers, but given that his email back and forth with Nick was sort of a secret (but only in the sense that nobody had asked if he was quietly discussing the most private aspects of his own physiology with an outsider, of course), he wasn't sure how such a conversation would go. On the other hand, if it was Agent Bishop tracking Godzilla, the turtles needed to act and fast.

Donnie decided he needed more to go on than the allegations in the email, something he could really use to gather some more data. He checked his past correspondence with Nick; HEAT had just handled a nasty fungus in an old storage warehouse, and Godzilla had put in an appearance when Nick breathed a little in and got sick. If Donatello knew Agent Bishop, he'd be investigating the area to see if he could pick up anything.

Maybe it was time for some random, totally coincidental scouting on the surface. Before he could think it much farther through, he stood up and moved towards the dojo, peeking in the open door, the signal that whoever was practicing within was willing to be interrupted. A closed door meant "do not enter if you value your head."

"Hey, Leo?"

"What's up, Don?" Leonardo didn't even open his eyes as he continued to move easily through the kata. With flawless precision, he sliced one katana through the air, bringing it to a halt exactly halfway through a candle.

"I just, well…" For one moment, he hesitated. The brainiac wondered if maybe he should tell Leo the truth, that Bishop was tracking Godzilla and he wanted to investigate, but he dismissed it. That would mean he'd have to admit his contact with Nick, and that would likely not go well, even if his older brother would understand.

"What is it?" The leader of the turtles opened his eyes then, unused to such a long pause from Donatello. He was not surprised to see his brother squirming a little awkwardly, as though he were about to do something dishonest – Leo could always read his brothers, and especially Don, who was generally the most forthright. But Don took a breath and seemed to settle himself more comfortably.

"I just wondered if we could go on a training run tonight. It feels like it's been a while since I've been out, and I want to stretch, you know?"

"Sure, Donnie. But is there something bothering you?"

"No," and the purple-banded turtle shrugged just a little too easily, "I just feel cooped up."

"All right," Leo replied, watching his brother closely. If it had been Raph or Mikey before him, he'd have made them tell him what they were obviously hiding by whatever means worked best. But with Don, it was better to wait. Donatello always came clean in his own time, one way or another. "But if you need to talk about anything, you know I'm here."

"I know," and the smile that spread across his face was entirely at ease. "Thanks, bro."

-==OOO==-

"Hey Donnie! Wait up!"

"What's gotten into him?" Leonardo asked as he landed on a rooftop next to Michelangelo.

"I know he's been coopin' himself up in his lab a lot," Raphael commented, "but I haven't seen Don this eager to get outside since he got better."

"You guys coming?" came a call from their brother, a little farther ahead. This area of the city was in transition from old manufacturing warehouses to upscale condos, and therefore pretty quiet. Still, it was far from their usual stomping-grounds, and though it wasn't unusual for one turtle or another to decide to wander in a new direction of an evening, it wasn't often Donatello doing the suggesting.

"Well, everybody's gotta air out their brain sometimes!" Mikey shrugged.

"Yeah and if you want to talk about air and brains…you know what? That's too easy," Raph sighed. He flicked the back of his youngest brother's head disappointedly.

"Hey!"

"Come on you guys," Leo admonished. "Donnie never does anything without a good reason. Let's see what he's thinking this time."

As the three made their way towards where Donatello was waiting, they saw their brother turn his head, as though he had suddenly spotted something. All at once, the braniac turtle rolled to the side, coming up in a tense crouch. A heartbeat later, his bo was in his hands and he was leaping out of sight. Leonardo signaled for silence and the other three charged forward with as much speed as they could manage – their brother was on alert. When they reached the place Donatello had been standing, they understood why.

Below, an old warehouse looked like it had seen better days: a significant hole had been punched in one side, leaving almost the entire southern wall gaping open. Inside, the turtles could make out the outline of a tape perimeter, and a few pieces of new, shiny equipment scattered around the area. And standing in the shadows was the unmistakable outline of one of their most hated adversaries, calmly giving orders into his cell phone.

"Bishop!" Mikey breathed.

"That guy! Time to make him sorry for what he did to Don," Raphael snarled, twirling his sai in anticipation.

"Wait. Where is Don?" After a moment, Leo spotted his brother behind some cover off to Bishop's left. The scientifically-minded turtle had pulled out his laptop and seemed to be working furiously. "Let's get there first."

Raphael put his weapons away and followed the eldest turtle in stealthily joining Donatello in his hiding place on the ground. Peeking at his screen, they could see that the brainiac had managed to use Bishop's distraction on the phone to hack into the agent's own equipment. He was rapidly pulling up and saving everything he accessed, one file at a time, fingers flying over the silenced keyboard.

"What's he doing here?" Leo asked in a voice softer than a whisper. In response, Donatello pulled up a picture of Godzilla, evidently taken from a satellite above. Then he pointed to a series of document names in a folder: "current location," "DNA analysis," "genetic properties," "correlation with terrapin samples," "potential applications."

"Dude, he's stalking Godzilla the way he did us!" Michelangelo realized. Don nodded.

"So what're we gonna do about it, fearless leader?" Raph asked, the angry challenge still present even in the quiet whisper of his voice.

"If Bishop finds out a lot about Godzilla, could it be bad for us?" Leo asked his brother, fearing he knew the answer. Donatello nodded again, definitively, and closed and stowed his laptop.

"He could do ten times what he did before on accident," the brainiac confirmed.

"Then we've got no choice. You've got his data, right? So he doesn't need it anymore."

-==OOO==-

As Raphael picked himself up and kicked off the trash can that had marginally broken his fall, he wondered again how exactly a scrawny human had picked up such incredible strength and speed. Fighting Bishop four on one was unfair, and not to the agent. The four turtles could barely hold their own against him, for reasons no one understood, and even when they had been with Splinter, Casey, and April they hadn't been able to defeat him.

"But you're gonna go down this time, Bishop. For what you did to Donnie," he growled, crouching as he launched another furious attack.

"What are you talking about? I saved Donatello, Raphael. Without me, your brother would still be a dangerous, mindless animal." The agent's voice was smooth, taunting. He easily deflected the blow Raph levied at his head, dodged an incoming kick from Leonardo, and managed to pull the second of Michelangelo's nunchaku from his grip, the first already decorating a ladder a half-block away.

"It was your fault he got that way in the first place!" Mikey shouted, his jovial voice somewhat less cheerful than usual.

"You've got to work on cleaning up your own messes, Bishop," Donatello commented, running into the fray with speed and aiming his bow for the agent's legs.

"No, Don, this is our fight!" Leo said, interposing himself and attacking directly. "You leave this to us."

"As you wish," Bishop replied. With a kick that looked effortless, he managed to pull both katana from Leo's hands, and a moment later had flipped Raphael's sai away with the borrowed nunchaku of Michelangelo's. The three turtles crowded around him, wholly unarmed, striking as best they could. But still Bishop evaded them.

Donatello stood back, bo in his hands, unsure. On the one hand, he was inclined to follow Leonardo's orders and let them handle it, but on the other, he wanted to help, wanted to take back some of his own after what had happened. He was about to move when everything changed.

"I think it's time we get serious, gentlemen," Bishop said evilly. A moment later, he had knocked Michelangelo and Leonardo into dumpsters, and Raphael was on his shell on the ground. Before any turtle could react, the agent reached into one of his many pockets and pulled out a hand-held jet injector filled with an ominous orange liquid. Raphael froze.

"Don't come any closer," Bishop threatened, his voice still even. He waved at where Leonardo and Michelangelo had begun to advance on him again. "This is a very new cocktail and I'm not quite sure how Raphael will respond to it. Unless you want to find out, I recommend you stand back." Leo waved his youngest brother to stand down, slowly circling until the two of them could see both Bishop and Raphael clearly. Their anger shook in every line of their bodies.

"I ain't really a fan of your doctorin', Bishop," Raphael taunted. "Your bedside manner could use some work."

Donatello, still in the background, suddenly realized he had an opening. If he charged, calculated the precise angle of attack, and hit, he could knock the syringe from Bishop's hand, he was pretty sure. But to do that, he'd have to put himself in range of it. The purple-clad turtle could sense his brothers buying time, trusting that he, mostly forgotten in the moment, would take action. He gripped his bo hard, hard enough that it hurt. He had to help, had to end the stalemate before something happened to Raphael. But getting that close to Bishop, to another chemical that could do what the last one had done absolutely terrified him. A trickle of sweat ran down his face and he could feel horror in the pit of his stomach. His mind circled in scenarios, each worse than the last, and his stomach churned violently. He couldn't think straight, he was falling, he was going to be sick. And he hated himself for the fear.

"Time to see how this works," Bishop said, a wicked eagerness in his voice.

A tiny terrified noise made its way out of Michelangelo's beak as he stared. Bishop was going to inject something into his brother that might make them lose Raph as they had lost Don for a while. And there was Donatello, paler than they'd seen him since just hours before he'd started to transform, his face almost wild in fear. Somebody had to do something! But as he started to charge, to stop Bishop, to do anything to save Raph, vaguely aware of Leonardo at his side, someone else moved.

With a cry that was as much dry heave as true vocalization, Donatello blurred forward. Every nerve and muscle in his body was screaming to go the other way, but he couldn't, he wouldn't leave Raphael to that fate. Bishop turned, but Don had closed the distance and, thanks to the long reach of his bo, was already there. He hit the agent's wrist with a crushing blow, sending the pressure spay-injector flying. Raphael took the opportunity to land a solid punch in Bishop's stomach as he rolled out of the way.

"Donnie, no!" Leo's voice rang out.

Donatello looked up in time to see the syringe-casing coming towards him.

-==OOO==-

"No! Not again!" Raphael felt himself near to exploding. Donatello's head moved with dreamlike slowness, down to where the hypo-spray had impacted just above his plastron, a few drops of liquid still dripping from the rough gash it had left after shattering. Then the turtle looked up, his colorless face becoming even paler in the streetlights.

"Pity. Would have been nice to see what that would do to an untainted turtle. Do let me know how the reactions turn out," Bishop shrugged triumphantly. With incredible speed, the agent avoided a furious rush by Michelangelo and Leonardo and began to retreat for the shadows.

"Donnie?" Leo called. He knew it was a bad idea to let Bishop go, but his first concern was his brother. "Donatello, say something."

"Snap out of it Don!" Mikey said urgently, gathering near. But even with his anxiety high and tightening his throat, the youngest turtle could not quite bring himself close enough to touch his brother. What if that stuff was going to turn him into a monster again?

Raphael, however, had no such hesitation. He gripped Donatello's shoulders tightly and shook him a little. "Come on, brainiac. Come back to us."

Donatello's fuzzy eyes regained their focus. A hand absently moved to the blood trickling from the wound. The jet injector had struck him below the collar-bone above the plastron, releasing its chemicals and then falling apart on impact, leaving a few nasty cuts where jagged glass had hit. He took a bit of the yellowish fluid on a finger and stared at it.

"I'd…really like to get to a lab, if you don't mind," he said shakily. He seemed to have trouble focusing on anything, even the turtle inches from his own face. Even so, pushed his brother's hand with an elbow, keeping Raphael from touching the wound.

"You got it. Hang tight," Leo ordered, steeling himself. "Mikey, get the weapons. Raph, you've got Don. I'll call ahead." He locked his brother in a steady gaze, nearly wincing at how wide Donatello's eyes were. "It's going to be okay, I promise. If you feel anything, tell us. And fight it. We'll take care of the rest."

"Why'd you do it?" Raph asked his brother. Don waved him away, absently. "Why can't we help you?"

"Contamination. Dangerous," he replied, foggily. As if reading his mind, Michelangelo was suddenly beside them, an old rag in his hands.

"Here. Will this help?" His eyes were wide.

"Perfect," Don tried to smile. He carefully wiped every droplet of liquid he could from his chest and neck, then tucked it around his plastron as best he could. "Thanks, Mike."

"Yeah, we're on our way," Leo was saying into the phone in a tight voice. He snapped the Shell Cell closed decisively. "Okay. I'll take point. Mikey, you've got the rear. Raph, stay with Don. Leatherhead says not to let him fall asleep and to keep him from exerting himself if you can help it, to slow down the spread…" he trailed off, his throat tight. "Let's move."

Raph gave his brother an arm to lean on, but once the turtles were back on the roofs, he gave up on that idea completely. He could tell just by the sound of Donnie's breathing that his brother was tiring. After the second jump from one building to another, he pulled the genius across his shoulders.

"Raph! I can walk," Donatello protested, and the weakness of his voice appalled them both.

"I know ya can," he replied. "And normally I'd let ya. Just not tonight. Besides," he said, and his usual gruff tone softened a bit, "you never answered my question."

"Question?"

"Why'd you do it? Why'd ya put yourself in danger like that?" Raphael felt his brother sigh. And shiver. His skin was getting cold. That was definitely not a good sign.

"You'd have done it for me," Donatello said. "Best I can do, right?"

"You can do a lot more than that, Donnie," Raph replied heavily.

-==OOO==-

It was a long, difficult trip home. When the four brothers finally got to the lair, taking the most direct route rather than the most secret and secure, everyone was waiting for them. Leatherhead already had his coat on, eyes narrow with concentration. The lab was flooded with light, and two or three computers were up and running various scenarios. April, also in a lab coat, stood next to a cot, openly worried as she laid out various gadgets and prepped her laptop. Casey Jones, for once serving as more than a pain in the neck, was in the kitchen, attempting to make tea without breaking anything, and mostly succeeding. Master Splinter met them at the entrance.

"My son? How do you feel?"

Donatello, who had been in a daze since the chemical had entered his bloodstream, looked up at his father and sensei, and again his eyes cleared. Leonardo, having taken a turn at supporting him, felt his brother's skin suddenly go much colder as the younger turtle broke out in another cold sweat. He tried to smile confidently, but the expression fell flat.

"Scientifically speaking, I've been exposed to an unknown chemical that is definitely interacting with my endocrine system as well as my…" he trailed off, eyes glazing over once more.

"Get him on the cot at once," Leatherhead said, his gentle voice punctuated with the same sort of sharpness Donatello had when thinking in precise scientific or medical terms. The voice that meant his heart was as far from his mind as he could make it – the crocodile was probably as worried as the rest, though, as he would say himself, he would worry later. As Donnie began to shake, Michelangelo took his other arm, and between himself and Leo they mostly carried their brother to the ready bed. As soon as Donatello was laying down, he seemed to fall immediately unconscious.

"Is he gonna be okay?" Raph demanded.

"I do not know – I have not yet begun to examine him," Leatherhead replied. "In the meantime, did any of you come into contact with this liquid?"

"No, just Donnie. He wouldn't let us move him until he was sure we wouldn't touch it," Leo answered slowly.

"Good. The exposure is limited, then. If you had touched it, we might have a much bigger problem."

"What can we do?" Michelangelo wanted to know. April put a hand on his shoulder.

"Just let us run some tests. We'll know more soon."

"Until then," Master Splinter said quite sadly, settling himself at the side of his gentlest son, "we wait."