Chapter 1

The lights of the city shone brightly beneath them as the turtles leaped from rooftop to rooftop, cutting through the darkness with great speed and agility. Car horns beeped, people shouted, and somewhere in the distance music was playing, but high above the streets, somehow removed from it all, the four brothers traversed a world of their own, in silence.

Suddenly the leader stopped at the very edge of a building and his brothers came up short behind him a second later. Together they stared down at the building across the street – an ancient brick structure, long since abandoned, which appeared to have once been used as a garage for large vehicles; an old fire station, perhaps. The building was completely dark and, to all appearances, completely empty. The turtles, however, knew better.

"This is the location," stated Leonardo in a low voice.

"Then what are we waitin' for?" asked Raphael, beside him. "Let's get down there and crush some Kraang!" Twirling his sais impatiently, Raph hadn't even bothered to keep his voice down.

Leo sighed. "This is a stealth mission, Raph. We are here to discover what sort of 'experiment' the Kraang are up to."

"Why?" growled Raph. "If we go in there and destroy all the Kraang, I'd say that will ruin their experiment!"

"Because, doofus, we have no idea what they're up to," interjected Donatello. "Whatever they're doing in that garage down there might be only one small part of an intricate plan. We have to find out what it is in order to stop them."

Leonardo noticed his brother sounded tired as he gave Raph a much less detailed explanation than he was accustomed to. It had been late last night that the Kraang communication orb in Donnie's lab had started beeping and blinking with red dots. Full of excitement, the genius turtle had set instantly to work deciphering the message. Finally, at about eight o'clock this morning, his brothers had heard a shout of "Eureka!" coming from the lab, and Donnie had emerged, coffee in hand, with the triumphant announcement that he had cracked the code. The Kraang, he had informed them, were planning to conduct a new experiment that night, at the address the turtles were currently surveying. Watching his younger brother stifle a yawn, Leo realized that Donnie had never gone to bed last night and wondered if all the coffee he had drunk would see him through their mission tonight. He was about to inquire how his brother was feeling, when his thoughts were interrupted by Michelangelo's voice.

"Dudes! We got company!" He was pointing, with an eager look on his face, toward a row of white vans that were pulling in behind the garage. The turtles recognized the Kraang's vehicles instantly.

"Alright, guys," Leo said, tensing for action, "follow me. And remember," he glanced back at Raph, "stealthily!"

Raph rolled his eyes, but nodded at Leo. Within a few seconds the four ninjas were on the roof of the garage, prying open a dirty skylight. Without a sound they dropped inside, landing on an old wooden rafter.

From their vantage point, the turtles could see the whole inside of the building. Barely any of the city's illumination filtered in through the grime on the windows, leaving most of the room shrouded in shadow. A thick layer of dust covered the ground. There was nothing else to see save a few old wooden crates and boxes stacked haphazardly about, left there years ago, their contents forgotten. Several Kraang droids, holding laser guns, moved about the dusty floor, aimlessly, it seemed, as though they were bored, or perhaps waiting for something.

"For a Kraang headquarters, it sure isn't very Kraangy," commented Raph, thankfully in a very low voice this time.

Leo had to agree with him. Where was the supposed 'experiment' the Kraang were working on? He had expected to find a portal, or a high-tech weapon, or at the very least some mutagen or something, but this empty, abandoned building seemed more befitting the Purple Dragons than the Kraang. If it weren't for the robots meandering around below them, he would have thought they had come to the wrong place.

He glanced at Mikey and Donnie. His youngest brother was bouncing slightly, grinning, and seemed to be eagerly awaiting Leo's order for action. Donnie, however, was scanning the room with the same confused expression Leo knew his own face must bear. His purple banded brother glanced at him and shrugged, apparently unable to offer an explanation for the apparent lack of Kraang technology.

"OK, guys," Leo whispered, "here's the plan - " Before he could finish, however, there was an ominous crack as the rotted beam they were crouching on suddenly decided it could no longer bear their weight and chose instead to come crashing down directly in front of three Kraang bots. Reacting instantly, the four turtles landed deftly on their feet, their weapons already drawn.

"Alright, Leo!" cried Raph with a grin. "I like this plan!" A few seconds later the three robots lay crumpled at his feet, the squealing brains inside scuttling away like scared spiders.

The next instant the room was filled with laser fire as the rest of the Kraang became alerted to the turtles' presence. The four brothers dodged this way and that, avoiding the lasers and taking down all the droids they came into contact with.

Leonardo kept an eye on his brothers at all times, being constantly aware of what each was doing, and any potential danger they might be in. Out of the corner of one eye, he saw Mikey back-flipping over two Kraang at a time with a shout of "Booyakasha!" He caught them both in mid-air with his twirling nunchakus and landed in time to stick his tongue out at the brains popping out of their broken bodies.

Leo sliced a droid in half with his katana, while at the same time watching Raph stab his sais into three bots in succession, seemingly without effort. Glancing a bit further away, Leo saw that Donnie had just felled a Kraang droid with his bo, and was now looking intently into a far corner of the huge room, apparently listening. Leo did not have time to discover what he was listening to, however, for he suddenly had four Kraang on him all at once, and became, understandably, distracted.

In fact, Donatello was listening to the conversation of two of the Kraang, who seemed to be somewhat in charge. Having separated himself from his brothers during the fight, he was no longer in the middle of the fray and managed a spare moment to sneak closer in order to hear what they were saying.

"Kraang was correct in the knowledge that the ones known as the turtles would come to this place."

"Affirmative, Kraang. The ones known as the turtles are now in this place, so the time known as now would be a good time to be beginning the experiment known as Experiment Five in this place."

Donnie's brown eyes went wide. 'What?' he thought. 'They were expecting us?' He immediately began rushing back toward his brothers, taking out two Kraang on the way. All weariness had left his body. Nothing caused an adrenaline rush like fighting alien robots!

"Leo!" he shouted. "Leo, I think this is a trap!"

Leonardo looked up from the decapitated droid at his feet. "What? What makes you say that?"

Donnie very quickly repeated to his brothers what he had overheard. Leo immediately began making a plan. Since they could no longer reach the skylight they had entered by, the only other means of escape were through the two doors – one at the back and one at the front of the building. Before he could call a retreat, however, both exits were suddenly blocked by several more Kraang entering through the doors. These newcomers were toting different guns – sleek, black guns with small, glowing blue canisters perched on top of them.

"Uh, what's the plan, Chief?" asked Raph cheerfully. He was in his element and didn't seem at all phased by the appearance of the new weapons.

"Take these guys down, and then retreat through that exit," Leo explained simply, indicating the door in the front of the building. The other three nodded their approval, and Raph immediately began charging at a group of the bots holding the strange guns. A couple of them fired their weapons at him, but the agile turtle dodged the projectiles with ease and the bullets struck the wall instead, near where Mikey was standing. Rather than glancing off the bricks, however, the ammunition hit the wall with a small splat. Mikey turned to look in wonder at the three glowing, blue splotches of thick liquid that now began to drip down the wall.

"Whoa, dudes!" he shouted excitedly. "The Kraang are using paint ball guns now! This is awesome!" He reached out a green finger to touch the glob of shiny 'paint', but Donatello was there in an instant and batted his hand away.

"Don't touch that!" he cried. "It's not a paint ball!"

"Donnie, what is that stuff?" cried Leo as he dodged more of the strange projectiles aimed at him.

"I don't know yet," Donnie called back as he pulled a phial out of his belt. "Let me get a sample of it and I can take it back to my lab and analyze it."

"OK, but hurry up!" Leo was moving quickly, trying to reach the Kraang while avoiding being hit by the glowing 'paint balls'. Raph had already taken down one of the new droids, and had disarmed a second, but Leo could see that the others, who had come in by the back door, were fast approaching, and Raph didn't see them. He desperately tried to reach his brother, but there were just so many robots, and they were shooting furiously at him. It was all he could do to avoid being shot.

Donnie slapped Mikey's curious hand away again as he scooped up the mysterious substance into his phial, corked it, and replaced it in his belt.

"Come on," he said to Mikey as he twirled his bo staff, "let's go help Leo and Raph!"

The two joined the fray just in time to hear Leo call out, "Raph! Look out!"

Raph turned his head to discover the source of his danger, but was not quick enough to move aside before a small, glowing sphere struck him on the back of his shell with a splat. The other three looked on in horror as they saw the small spot of glowing ooze on Raph's back, but they were very quickly surprised to discover that Raph barely reacted to the shot at all. He looked at it with some surprise, and then turned and went back to fighting the Kraang droid he was currently engaged with. The new weapon didn't seem to have hurt him at all!

Despite this rather encouraging development, the other three did not let their guard down, but continued to avoid the bullets as they fought their way toward the front door. They were nearly there when one Kraang droid managed to trip Mikey up and in an instant it had shot out its metal hand and pinned him to the floor by his neck.

Donnie, who was closest, gave a cry and rushed to his aid. Before the robot had decided what to do with Mikey, now it had him pinned, Donnie had cracked it over the head with a furious swing from his bo, and sent it crumpling to the floor. As he reached a hand down to help Mikey up, however, Donnie had momentarily taken his attention off dodging the glowing pellets, and one suddenly struck him on the arm.

He cried out, more from surprise than pain, for indeed, it hadn't hurt him in the slightest. It simply felt cold and wet. He tried to brush the substance off his skin, but found it had already soaked in, leaving a glowing blue mark that couldn't be rubbed away. He frowned at it curiously, but was soon distracted again, for the fight was still in full swing.

Mikey had managed to get to his feet on his own and jumped full force toward a group of Kraang droids. He twirled his nunchakus expertly as he leaped, ready to bring them down with deadly accuracy on his foes as he landed. He let out his battle cry in mid-air, but he didn't get farther than "Booya-" before it was cut short by a large splat directly in his face. He landed forcefully on the offending Kraang droids, taking them down as he stomped about, clutching his face and crying out, "Aaargh! My face! They got my face! Ack! It's in my mouth! Blech! Bleaaach!" He spat several times, trying to rid his tongue of the horrible taste.

A few yards away, Leo, while fighting a few Kraang of his own, was watching his youngest brother's antics with concern. The freckled ninja's nose and mouth were now glowing blue, and though no ill effects had as yet been seen, still Leo was sure that whatever the Kraang were shooting at them could not be a good thing. They had to get out of here! He sliced another robot in two, ignoring the squelchy sound of the brain as it crawled away. Looking up, Leo noticed that Raph, with help from Donnie, had managed to clear away all the droids near the front door. Their retreat was open! He signaled to the two by the door and they immediately headed for the exit, while Leo ran to help Mikey, who was still dancing about with his hands over his face.

"Mikey, come on! We're leaving!" Leo shouted as he grabbed his little brother's arm.

Mikey pulled his hands away from his glowing mouth and pointed to it. "Dude, look! They got my face!"

"I know, I know!" Leo cried impatiently. "Donnie can fix it in his lab. Let's get out of here!" At that moment, Leo felt a cold splash on the back of his leg and looked down to see a blue splatter over his green skin.

"Oh no, they got you, too!" cried Mikey in a panic, pointing to Leo's leg.

Leo wasted no more time, but pulling Mikey's arm, he practically dragged him to the exit. He just had time to notice that the Kraang were no longer shooting at them. In fact, all the robots had suddenly ceased firing and were walking toward the back exit. Not pausing to wonder about this, Leo pulled his youngest brother out the door and into an alley across the street where Raph and Donnie were waiting for them.

"Hey, are you guys OK?" Donnie greeted them.

Leo was about to answer in the affirmative when Mikey burst out, "NO! Look what they did to my face!"

Raph couldn't help snickering as he looked at the glowing blue splotches all over Mikey's mouth and nose. "Well, some might say that was an improvement," he said, earning himself a glower from Mikey.

Donnie suddenly noticed Leo's leg. "Leo, you got hit, too?"

"Yeah, just as we were leaving. Donnie, do you know what this stuff is? I mean, it doesn't seem to do anything but glow."

"I have no idea. Let's get back to the lair and I can analyze it properly."

As Raph slid the manhole cover back into place and trotted through the sewer tunnel after his brothers, he suddenly realized that the cold spot on his back where he had been hit seemed to spread. Within a few minutes the whole back of his shell felt cold and numb and he could feel the coldness sinking deeper into his body. Not being one to complain, he ignored it and continued to run through the tunnels.

A moment later, Raph heard Mikey whine, "Guys, my face has gone all tingly!"

"Yeah, and my arm's numb and cold!" added Donnie, shaking the appendage still bearing the small blue mark.

"Come on, let's hurry back to the lair!" called Leo. "We're almost there!" Raph noticed with concern that his oldest brother wasn't walking properly. He seemed to be limping on his blue-splattered leg, as if it wasn't functioning correctly.

All four of them increased their pace, panic showing clearly on Mikey's glowing face. Just as they jumped the turnstiles and landed safely in the lair, the pain struck. It hit Raph like a physical blow to his shell and he collapsed onto his hands and knees with a cry. It felt as though someone were crushing his shell and ripping it into tiny little pieces.

Donnie instantly moved toward his brother, crying out, "Raph! What's wrong?" But before he could reach him, he, too, collapsed with a scream of pain, clutching his arm.

A moment later, Raph was vaguely aware that all of his brothers were now screaming in agony, but there was nothing he could do. The pain had now shot like fire from his shell into his shoulders and down his arms, and he was paralyzed by it. He cried aloud again as it reached his hands and he felt as if his fingers were being torn apart. Now his face was burning, too, and he felt sure someone had dropped concrete blocks on his feet and crushed them.

In another part of his brain, Raph heard Mikey's agonized cry, "Aaargh! It's killing me! I'm dying! I'm dying!"

Raph couldn't bear the thought of his baby brother experiencing the same torment he was, but he was helpless to relieve him. Every inch of Raph's body was on fire, shaking with pain more excruciating than anything he had imagined. He squeezed his eyes shut and curled his body involuntarily as he thought to himself, 'Mikey's right. We're all going to die!'