Disclaimer: I own none of the characters contained herein.

Author Note: I have in various places in this fic used my extremely limited knowledge of weaponry. Feel free to let me know should I make any mistakes regarding them.

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12 Years Later…

Leonardo entered his room, closing the door quietly behind him and deciding to meditate for a while. His training session with Master Saki had been a gruelling one, but he was grateful to his Sensei for allowing him the one-on-one time to improve his ninjitsu skills. It had been his third training session of the day; the first with his three brothers and the second with the Foot soldiers. He hadn't always felt the need to train so hard, but since Karai had been sent to Japan to oversee the Foot operations there, Leo had been at something of a loose end. He didn't feel slighted exactly, he was still young and Karai, several years older, had not only earned the opportunity given to her but she had the added advantage of being human rather than humanoid. It was difficult enough gaining the respect of the new recruits to the Foot clan when they realised their initial training would come from a five foot talking turtle, taking over an already established branch of the Foot, particularly one as historical as the Japanese branch, would be too difficult.

Still, he couldn't help feeling a little jealous. He trained hard and was at least the equal of Karai. They had sparred together enough for him to know that. And she was going to live in Japan, a place he had always wanted to go.

And he was going to miss her.

Karai had been a constant in his life since he and his brothers had been rescued by the Foot clan. Master Saki had discovered the heinous experiments his ancient enemies had been performing on innocent creatures and although his discovery had come too late for most of the lab animals, he had managed to save the baby turtles that had been exposed to some form of mutagen. He had taught them all about ninjitsu and kept them safe in the Foot headquarters. Leonardo felt honour-bound to repay their Sensei's kindness by becoming the best warrior that he could be and serving the Foot clan loyally. And Karai felt exactly the same, Master Saki having rescued her after she was orphaned in Japan. They had discussed it often.

Master Saki had his faults of course, but he was only human. What most disturbed Leo was how short-tempered his Sensei could be. There was never any warning; one moment he would be calm and collected, the next lashing out. Leo hadn't been on the receiving end of one of his tempers but one of his brothers had and still bore the scars to prove it. For a while after that he had wondered if he and his brothers should run away from the Foot headquarters, but in the end he had realised that four pre-teen mutant turtles were going to attract attention no matter where they went. Now he was glad that they hadn't. For the most part their Sensei was thoughtful, almost paternal toward them. Now they were getting older, it wouldn't be long before the four of them would be joining the Foot ninjas regularly on their missions. They had been on one or two, all of them proving they could hold their own and were just as talented and stealthy as the human members. Master Saki had promised that they would be needed very soon on a mission of particular importance but had refused to divulge further information. In the meantime, they were to go out in the field with the other Foot ninjas whenever there was a job for them to do.

The Foot had no missions that night and Leo wondered if he should seek out his brothers and maybe they should spend some time together. They had grown up together and as the only mutant turtles in existence, they had a bond. But that had weakened over the years, with all of them pursuing different interests and wanting different things. Donatello always seemed to be busy with his scientific studies. Raphael was spending altogether too much time with the Hun to make Leo comfortable – he had no reason to dislike Master Saki's trusted ally but that didn't change the fact that there was something about the Hun that Leo distrusted. And Michelangelo was more likely to be hanging out with the younger Foot ninjas than he was with any of his brothers. Leonardo was just as guilty of neglecting their family ties as his brothers were and he knew it – always trying to improve his ninjitsu skills in order to better serve the clan. He owed Master Saki that much at least.

Mind made up, Leo abandoned thoughts of meditation and wandered off to find his brothers.

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Donatello narrowed his eyes as he made some alterations to the mouser with a screwdriver. The machine was a technological marvel, a testament to the genius of Baxter Stockman, with whom Donnie had been working for several months. He was grateful to Master Saki for affording him this opportunity – to be at Stocktronics, working with Stockman, was a dream come true for the turtle. He had learned a lot about engineering and had been able to put some of his own theories to the test. It was what he had always wanted.

And yet…there was something about Stockman that Donnie instinctively distrusted. The man wasn't particularly likeable, his ego huge and his talk always boastful, but Master Saki had warned him about that before he even met the doctor. It was something else, as if Stockman had only the most tenuous grip on normality and was too involved in his own delusions of grandeur to pay attention to the most simple of things. Stockman was a bully, a weak bully with no real power aside from his intellect, wanting revenge on a world he seemed to think had slighted him.

Try growing up as a five foot tall mutant turtle and tell me how the world treats you badly, thought Donatello as he made another adjustment to the mouser, one that would hopefully increase its durability. Master Saki had pulled him aside not long after he was introduced to Stockman and asked the turtle to keep an eye on the doctor, obviously having some misgivings of his own.

"Stockman cannot be trusted," Master Saki had said. "He is of use to the Foot clan but I have no doubt that should a better offer come along, he will betray us without remorse. Should anything arouse your suspicion, I should like you to inform me."

"I will Sensei."

But so far, Stockman had shown no sign of betraying the Foot. In fact, he was as excited about the mouser project as Donatello himself, claiming that the project was the key to great riches. Then he would give the turtle a sideways look and smirk, as if Donnie didn't know what he was talking about. But Donnie wasn't as naive as Stockman seemed to think he was and had a good idea of what the mousers other uses could be. It wasn't just rats they could seek out, as he was aware from his work on the machines.

Donnie rubbed his eyes and sighed as he finished his work on the mouser. Now all they had to do was test the robot out and if the upgrades were advantageous, the changes could be integrated to the rest of the machines. The test runs the previous week had all been a success but success was no reason not to continue improving things. The mousers had jaws like steel traps, able to chomp through bricks and mortar as easily as they could the hide of a rodent. Some of them had been lost as others caused mortar and bricks to fall on them as they chewed their way through water mains and walls deep down in the sewers…

The sewers. Letting the mousers into the sewers had caused Donnie some troubled thoughts and he had no idea why. It was the perfect testing ground for the experiment, no one to interrupt the test runs, no suspicion should anything go amiss. So why did he feel so uneasy about holding the tests there? It made no sense and Donnie hated things that made no sense.

Glancing up at the clock, Donnie decided to test the mouser's upgrades in the morning. He had told Stockman he would only be another ten minutes and that had been three hours ago. The doctor was long gone and the building would be empty. Perhaps when he got back to Foot headquarters he could see if Mikey was up for a movie and maybe some pizza.

The soft hum of the elevator took him by surprise. The only people authorised to descend to this level of the building were himself and Stockman, and of course the others working at Stocktronics had no idea that Donnie even existed. And the elevator was hidden, activated only by a secret password on Stockman's personal computer, meaning that it had to be Stockman in the elevator. But some sixth sense made Donnie duck into a hiding place, relying on his ninja training in stealth and invisibility to keep him out of sight. The lower lab wasn't the best place for that. The floor was taken up by a conveyor belt system that was churning out mousers and the observation rooms were Perspex throughout. Only the control area had any kind of cover.

The elevator doors opened with a muted 'ping' and some one stepped out. Donnie had been unprepared for the sight of Stockman's lab assistant. He knew she didn't have security clearance to be down here. He knew a lot more about her than was strictly necessary, although wild horses wouldn't have dragged the confession from him. The room where he did most of his work was hooked up to the security system and he had often observed her as she worked, unaware that she was being watched by a mutant turtle. April, her name was. April O'Neil.

"Finally," he saw her mouth as she stepped onto the walkway and headed for the control room, her attention taken up by the mousers being created below her. So intent on the sight that she didn't notice walking through a motion detector, giving herself away without even realising. Donnie winced. The girl was toast.

"I don't care how bad the city's rodent problem is – this is serious overkill." She strode briskly over to the computer at the desk and sat down, not noticing as she passed Donnie's hiding place, typing rapidly on the keys. The elevator doors slid shut silently and she didn't hear the humming as it ascended again.

Donatello heard. He knew that the only way for the elevator to be going up again was if some one had summoned it and that some one had to be Stockman. April was in a lot of trouble and she didn't even know about it.

There were several options open to him, but he decided to take the wisest one and remain where he was until he found out what was going to happen. Maybe nothing would. Stockman might choose to just fire her – unless she found something incriminating on the computer.

Her slim fingers tapped on the keys and she irritably brushed a strand of red hair behind her ear. "Rat problem my eye. What are you really up to Stockman?"

Her voice masked the 'ping' as the lift once more opened, this time Stockman walking out. "Now now Miss O'Neil. That would be telling."

With a gasp, April rose and turned to face Stockman. She backed away as he approached; evidently realising she had just landed herself in a lot of trouble. Much to Donnie's relief, Stockman didn't seem to realise he was still there either. But then, why should he? As far as the doctor was concerned, the turtle had gone homes hours ago, there was no sign of another person in the room and he was all alone with his lab assistant.

"Suffice it to say, my mousers will make me a very rich and powerful man." Stockman had his hands behind his back and Donnie heard the electronic whine as the large window behind April slid down, indicating that the doctor was hiding a remote device.

"But – aren't you already a very rich and powerful man?"

"Ah, Miss O'Neil! So brilliant, yet so naïve." Stockman adjusted his glasses and shook his head in mock dismay. "I shall truly miss working with you."

"What! You mean I'm fired?"

"In a manner of speaking."

The robotic claw that was typically used to pluck faulty units from the conveyors and deliver them into the control room moved through the open window, activated by the remote control behind Stockman's back. It grabbed April by the back of her lab coat and pulled her out through the window, leaving her dangling perilously above the mouser making machines. April yelled in panic, squirming against the grip of the claw until her lab coat tore, dropping her onto the conveyor belt that housed the finished mousers.

"I'm afraid I can't let you live Miss O'Neil." Stockman glanced out over the area, adjusting his tie and typing instructions into the keyboard, adjusting the mousers' settings. "You've seen far too much already and…well; let's just say I have trust issues."

Discarding her shredded lab coat, April gaped in horror as the mousers advanced. Grabbing a fire extinguisher from the wall, she aimed it at the robots, backing up slowly. "Keep back! I know how to use this!"

One of the mousers gave a metallic roar and April released the nozzle, sending a cloud of carbon dioxide at the robots. It didn't affect them at all; the same mouser coming at her in a run. Panicked, she swung the extinguisher at it, caving in its head. A second swing put the makeshift weapon right in the path of another mousers jaws and it ate through the metal easily, snatching the object from April and chewing it into pieces. Her last line of defence gone, the woman turned and ran. She dodged her way past a crowd of mousers and found the lever that released the doorway to the sewer.

"You can run Miss O'Neil." Stockman's voice caused April to turn back and send a terrified glance behind her. "But you cannot hide from my mousers."

Losing sight of April as she raced through the doors to the sewer, Stockman snorted and strode back into the elevator. She could only run for so long, trapped in the maze of dark, dirty sewers. When she tired, the mousers would finish her off. He pressed the button to go back up, feeling quite pleased with himself. Much as he hated to lose such a gifted assistant, it was a problem that he had dealt with himself and not had to involve that maniac Saki in. That alone deserved some congratulations.

As soon as the elevator began to rise, Donnie slipped out of his hiding place and went over to the still-open window. Through the cloud of carbon dioxide, he could see the mousers running out of the exit to the sewers, presumably still hunting down April. And that left Donatello in a quandary. She could have compromised the Foot with her foolish interference, cost them one of their most profitable sidelines by exposing the truth behind the mousers to the public. Master Saki would order her immediate disposal, of that he had no doubt. Sensei had been good to them but he brooked no interference with his plans, nor was he especially merciful.

On the other hand, what did she know exactly? Not much. Only that there was more to the mouser project than met the eye and that was hardly enough to expose Stocktronics as a front for something more sinister. And it wasn't as if she was a warrior falling in battle; she was a scientist being chased by a hoard of robots. She had expected to work in engineering, not fight for her life in a sewer.

Donatello hesitated for another moment, feeling the comforting weight of his naginata on his back, the weapon that his Sensei had chosen as being perfect for him and which he never went to the lab without. It didn't feel right to just leave her, it felt dishonourable, cowardly – but if anyone were to find out that he had tried to help her, Master Saki would be furious and all the turtles knew the consequences of inspiring the wrath of their Sensei. Any time they forgot, they just had to look at Mikey.

What was he going to do?

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She ran, no direction in mind as long as it would get her the hell away from the mousers. It was a rare day when she was grateful for her lack of social life, but right now all the extra time it had afforded her in the gym was very welcome. Even so, there was a difference between a leisurely jog on a treadmill with the top twenty playing in the background and being chased through ankle deep sludge by remorseless robots. She could feel the chill sinking into her bones, the acoustics of the tunnels echoing her splashing steps and ragged breathing. Behind her, she could hear the squeals that the mousers made, meaning they were still on her trail. And she knew there was no way to throw them off. They were too well designed, thanks in part to her.

Well done O'Neil. Couldn't you have been a bit less of a perfectionist about this job?

She entered a runoff point, giving her three different tunnels to choose from. Momentarily she paused, turning in a circle as she tried to get her bearings, think about where exactly she might be.

"Which way out? Which way out?"

She chose a tunnel at random and continued running down it, hoping against hope that the mousers would choose the wrong path. Not likely. They could read body heat and there was nothing else her size down here. She was history.

Her clothes were drenched from her initial stumble into the filthy water, making it more difficult to run, and she was finding it hard to see thanks to the dark and shadows. Stumbling out of the tunnel, she risked another glance behind her but couldn't see anything following her. She turned a corner and kept running, shooting another look over her shoulder and turning back just in time to avoid running into two mousers that had managed to get ahead of her. Turning back in the direction she had come in, her retreat was cut off by another two mousers. All of them advanced, leaving her no choice but to duck into another tunnel and go on running. But now her strength was ebbing, her stamina deserting her. She wasn't going to be able to run much further.

Her foot caught on something hidden under the murky waters and she fell, landing face down in the gunk. Her disgust was overridden by her terror and she scrambled to her hands and knees, manoeuvring into a sitting position and shoving herself backward as she realised the mousers were there, too many to avoid even if she had the energy to go on running. She couldn't even get to her feet. Her back hit a boarded up tunnel and she tried to pull the boards away, but to no avail. This was it. Her life was going to end down here in the dark and no one would ever find out what had happened to her…

A mouser leapt at her and she screamed, hiding her face so she wouldn't have to see when it buried its jaws into her flesh.

But the anticipated pain never came. Instead she heard a noise, like a blade slicing through metal, and the sound of machinery raining into the water. The light that had illuminated the tunnel, coming from the torches on the mousers metal skulls, died suddenly and plunged her back into darkness. Tentatively, she dropped her hands from her face and squinted into the gloom. The mousers floated in the water around her, destroyed. And there was a shadow before her, a person standing some distance away, too far into the dark for her to make out any features.

"Oh…oh! Thank you! Thank you so much! You saved my…my…" She trailed off as she realised something was wrong with the shadow. It was undeniably a person but the proportions were all wrong. The body wasn't the usual human shape. And it was short for a grown up, yet it surely couldn't be anything else, not if it could dispose of the mousers so rapidly.

And why would anyone be down here in the first place – unless they followed me…

The figure moved its head slightly, indicating to a space behind it. "There's a manhole a few hundred yards away. You can get to the surface that way. And I'd advise you to get out of New York and forget what you think you know about Stocktronics."

She blinked, anger beginning to break through her fear now that the mousers were neutralised. The voice was undoubtedly male but the attempt at authority was too forced, suggesting to her that the speaker was an adolescent. Being told what to do by a teenager, coupled with her near-miss with the mousers, was making her irritable. "What I think I know? I know that Stockman just tried to kill me!"

"And if you go shouting about it, I can't save you the next time. Lie low for a while April. Stay away from Stockman and keep what you know to yourself."

"How do you know my name?"

The figure shrugged. "Do what I said. If Stockman doesn't know you're alive, then he won't come after you."

She struggled to her feet as the figure moved backward and was lost in the shadows. "Wait! Who are you?"

There was no response. She made a cursory search of the tunnel but there was no sign of her rescuer although she did locate the manhole he had told her about. Suddenly desperate to be out of the dank and home, she scrambled up the ladder and fought to raise the lid, pulling herself out of the sewer and finding herself in an alley about three miles from her house. She had the keys to her apartment in her pocket but her purse was back at the lab meaning she couldn't get a cab, assuming one would even stop for her the state she was in. She was going to have to walk.

Life sucked. But at least she had a life, thanks to her anonymous saviour.

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Author note: A naginata is a weapon similar to a bo but with a blade on one end. I thought that the turtles may not have the same weapons in this fic as they would in the event of Splinter raising them. I've not completely decided on the weapons the other turtles will wield, so any suggestions will be taken on board. Leave a review before ya go!