As always, my thanks to those who read and reviewed the last chapter! This was supposed to be the last, but it got too long so I've chopped it in half. One more chapter (I keep saying that!) then the epilogue. Enjoy!

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As they reached the end of the air shaft, Donnie kicked off the vent and checked out the room. He'd had a good idea where the shaft led to, but it was gratifying to have his memories confirmed.

"We're in the weapons room," he told the others, leaping out of the vent and several feet down to the floor.

"Is there anything in here we could use?" asked Leo, looking around. He had always declined to use most of the tech available to the Foot simply because he preferred the honourable method of fighting with his swords than the short cut of bigger guns.

"There's things we could use, but is it a good idea?" Don examined a few things. Some of them he'd even worked on in the labs. "They're mostly heavy and none of us are experts."

Leo nodded. "We keep to what we have. No need to make things complicated. I don't suppose we can disable any of these?"

"Not without taking a lot more time than we have."

"Aw," said Mikey, picking up a random gun and tossing it from hand to hand. "We coulda had some fun!"

"Put that down lame brain," snapped Leo.

"Come," said Splinter. "We must remain on the move."

Reluctantly, Mikey replaced the weapon and followed the others. Until Splinter stopped walking and held out his arms to stop them.

"Wait!"

"What is it?" asked Raph impatiently.

"I sense a presence."

The four looked around doubtfully, seeing nothing. Mikey shrugged. "Nobody here but us turtles!"

They continued a few more moments before Splinter stopped again. "Something is here. Something that cannot be seen."

Don spun around, realising the truth. "Foot Tech ninjas!"

The turtles stood on guard, awaiting an attack – and without warning, Don's bo was kicked out of his hands and a moment later, an unseen kick sent him flying.

Raph slashed at thin air, hoping to hit someone through sheer luck. His sun and moon daggers hit nothing and within seconds had been knocked from his grasp. A vicious chop to the back of his neck landed him on the floor in a daze, cursing.

Leo swung around, trying to listen for the sounds of movement. For a second he thought he heard a footstep – and then his treacherous memory took him back to the night on the rooftops, the night that had nearly cost him his life...

...the sounds of footsteps in the rain, no one in sight...

He froze.

A moment later, the katana were kicked from his grip. He lashed out blindly, forgetting for a moment all of his years of rigorous training as he panicked, hoping only to get the guys before things got as bad as they did the last time this happened – and then a slam to his plastron knocked him half way across the room.

Failed, I'm gonna fail again...

Mikey leapt backward more from startlement than judgement and felt the air moving as a fist missed him by an inch. He continued to flip backward, hoping to avoid the blows until he could form a plan of some kind. But he ran out of room before a plan came to mind, landing on a platform with a lift mechanism on it. He'd played Resident Evil often enough to know what to do in this kinda situation. He hit the button and smirked as it rose.

"Ha! In your faces! Smoked your transparent butts!"

"Ahem."

The voice came from behind him. His heart sinking, Mikey turned, realising that somehow one of the Foot Techs had got behind him and still he saw nothing... but he felt it when a kick hit firmly in his plastron and knocked him off the platform. He hit the floor on his shell, hard enough to knock the wind out of him.

Splinter growled as he saw his sons knocked around in front of him, seemingly by thin air. Invisible assassins, meaning that sight was doing little but confusing them. They had to utilise other senses.

He closed his eyes, letting his superior hearing and sense of smell take over. Slightly to his left, he heard the ninja that had knocked Michelangelo from the platform jump from the machine, landing softly on the floor. Without a pause, Splinter leapt forward and delivered a brutal kick before the man could move, hitting the cloaking device on the ninjas chest plate and rendering him both visible and no longer a threat.

Sensing something behind him, Splinter turned and blocked another attack from a Foot Tech ninja with his walking stick. Leonardo, recovered from the previous blow, ran forward to aid the rat, lashing out at the air, not connecting. A moment later his feet were swept from beneath him and he went flat on his shell.

Splinter used the distraction Leonardo provided, leaping into the air and hitting the ninja full in the face, which wouldn't have given the turtles much of an advantage – save for the fact that Mikey was directly behind, just recovering his own feet. Turtle and ninja went down again, Mikey having the presence of mind to deliver an elbow that disabled the cloaking device by pure luck rather than good judgement. He'd been aiming lower.

Leo was back on his feet moments after going down, finally able to see the ninja and using a nerve grip that the Shredder had taught them many years before, one that would leave the guy unconscious for hours.

"Two down, one to go," muttered Raph, trying to work out where the final guy had gone. "What, is he too scared to face us?"

At that moment, an engine started up. The turtles turned toward the sound to see a heavily armed vehicle, with caterpillar treads and many weapons they couldn't even begin to guess the use of. And it was heading straight for them..

"You just had to say it," said Donnie, diving for cover.

"It looks like a tank got busy with an octopus!" Mikey stared at the vehicle in awe as it turned in his direction.

There was a whooshing noise and suddenly a small missile emerged from the vehicle and shot toward Mikey, Leo and Splinter. The three ran and the missile hit a van in the corner that might have been intended for surveillance but was suddenly reduced to no more than a smouldering heap of twisted metal.

The room was large enough that the vehicle had room to manoeuvre, but it also allowed the mutants the advantage of being more easily able to dodge. A second missile was fired, this one hitting high into the wall and shaking the skyscraper. Concrete and rubble fell to the floor, raising a cloud of dust.

The turtles and Splinter were focused solely on the tank, concentrating on finding some way to overcome it – so when the first Foot Tech ninja that Splinter had hit suddenly attacked from behind, none of them had been expecting it.

Splinter was suddenly lifted and thrown to one side, hitting a set of shelves hard. Its structure had already been weakened by the explosions and collapsed, burying the rat in tools and equipment, pinning him to the ground.

Don hurled an electric counter shock shuriken at the general area the ninja had been in, missing the chest plate he had been aiming for but opening a wound on the ninja that was not hidden by the cloaking device. Through narrowed eyes, he watched the way the pattern of blood moved before throwing a second shuriken, this one hitting the ninja and shorting out the gadgetry.

The other three had immediately run to help Splinter, who was struggling to free himself from beneath the shelves. He looked over their shoulders to see the tank bearing down on them. "Leave me!"

"Leave you? No way!" Raph pulled aside a heavy girder and grabbed Splinter's arm, helping to his feet and hurrying him away, the others leaping into the air – toward the vehicle. Leo aimed a flying kick to the seemingly empty seat, hoping he was right to do so, grateful when he was rewarded by his foot connecting with invisible flesh. The ninja fell from the vehicle, becoming visible Leo sailed to the floor after him, putting him out of the fight for good. Mikey was only seconds behind Leo, landing in the vacated seat and hitting the button that stopped the runaway vehicle, which came to a grinding halt.

Mikey grinned down at Donnie. "And you're always telling me not to press the shiny buttons!"

Leo glanced up at the gap in the roof left by the high-aimed missile. "We could use that to make a rapid exit..."

"No!" Donnie shook his head emphatically. "Those are some of the labs up there. The genetic labs. Trust me, you do not want to see what's up there!"

"Then we take the elevator shaft." Leo glanced down at the now-visible and very unconscious Foot Tech ninja. "They won't be giving away our location anyway. Or our existence."

"The elevator shaft?" Mikey looked at the others. "Why not just the elevator? It'd be easier!"

"Hello! Mikey!" Raph grabbed his brother in a headlock and tapped on his head. "We're ninja, remember? Stealth? Invisibility? Not giving away where we are through advertising the damn floor we just hit?"

Mikey escaped and stuck out his tongue. "No need to worry about me! Stealth is my middle name!"

"Can we just get on with this?" Leo went over to the elevator hidden in the shadows at the far end of the weapons room and attempted to prise loose the doors. After a moment, Raph went over to help and between them and their weapons, they opened the doors, which led high up into the Foot headquarters, although not all the way to the top. Or, to look at it from another point of view, several floors down to a quick and messy death.

"Is the car above or below us?" asked Donnie.

"Um..." Leo squinted up, then down. "It looks like it's below. I think I see it. Might be the ground though. Too dark to tell."

"If it's above us, we could all become turtle pancakes," grumbled Raph.

"But if it's below, we could shorten the trip if someone uses it!"

Leo tuned out Raph and Mikey, trying to remember everything that Mas – that Saki had taught him about learning to control his fear of heights. Most of the time now it was second nature and he didn't think about it, but every so often it cane back to him. Like now, when he could be crushed from above if he was wrong.

Taking a deep breath, he grabbed the cable and swung over the void, going hand over hand further up the rope. He felt the rope jerk every time one of the others joined him and soon they were all making their way steadily upwards. hopefully their whereabouts – and escape route – unknown.

The elevator shaft terminated at the seventy second floor, just as Leo had rather suspected it would. Many years ago, he and Donatello had used the same elevator to come to this very floor, planning to improve their ninja skills by practising against the traps laid all over the floor – and nearly had their shells handed to them. He didn't doubt the security measures were still in place.

"Remember this place Leo?" asked Don as he climbed out of the shaft.

"We nearly got our shells waxed, how could I forget it?" Leo managed a smile at his brother. "At least now we know what's lying in wait. All we have to do is not trigger any sensors."

"Easier said than done," replied Don. "Shredder's probably changed the triggers a hundred times between then and now."

"Agreed." Leo waited for the other three to get out of the shaft before continuing. "There's traps everywhere around here. Splinter, can you tell where any of them are?"

Splinter scented the air. "No, although I sense their presence I cannot locate their exact whereabouts."

"Then we go carefully," said Leo, giving Mikey a particularly meaningful look. It had been hard to remember a time when Mikey had been jocular just a few scant months previously, but something about their time at the farm, the way they had become closer, seemed to have awoken that side of him again. Much as Leo appreciated the humour sometimes, it could be unnerving when Mikey suddenly cracked a joke or began bantering with the enemy.

He need not have worried. The five mutants were all on guard, leaping lightly from place to place, Leo in the lead and the others following his exact steps. No alarms were triggered, no traps sprung.

In all their years living at Foot headquarters, the turtles had been confined to certain areas of the building. The price of violating the rules was a high one, as Michelangelo had found out. They had trained in Saki's private rooftop sanctuary, but had gone straight there from the opposite side of the building, where they resided. Only Leo and Donnie had ever been as high as the seventy-second floor at this side and none of them had been any further than that. They were in unchartered territory from that point onward.

The double doors at the far end of the corridor had the sign of the Foot emblazoned upon them. Leo pushed them open and the five stepped through into an open area, a courtyard hidden from the lower floors. The whole area was shrouded in a mist that seemed strange for the weather conditions, unnatural. The air was still, redolent with some heavy incense. The decor was the exact opposite of what the rest of Foot headquarters boasted, the high-tech gadgetry and security absent, columns and pillars made of worn stone leading to a heavy door, the only sign of modernity in the place.

"Cheery," muttered Raph, his voice sounding out of place in the mausoleum silence. The group made their way over to the steps leading to the door, although it looked impenetrable. Still, maybe there was another way into this part of the building...

And then they were all alerted to the noise behind them, quiet, stealthy and yet somehow sly; as thought the maker had intended them to be alerted. The five of them turned, weapons at the ready.

Raph glared at the figure, features hidden within the fog that enshrouded the area but his silhouette easily identifiable. He scowled, raising his daggers higher. He couldn't be seeing what he thought he was, it simply wasn't possible...

"Splinter," he whispered to the rat. "You weren't hiding something about when you found us, were ya? Like, maybe how we had another brother?"

"I hid nothing," replied Splinter, his ears lying almost flat against his skull. "And there is something different about this turtle to you four. He is not one like you."

As if to prove the rats opinion, the figure moved through the mist, coming closer. Raph widened his eyes. He had thought whatever it was had been closer – but as it turned out it was simply larger than them. Much, much larger.

And definitely a turtle.

It came in close, finally near enough for the four turtles to see what this other one who shared their shape looked like. Massive, maybe seven feet tall, bulky and heavily veined. It was carrying some kind of staff. And it was grinning at them with malicious good humour.

"Ho-lee shit..." Raph began and got no further. Another step forward revealed the creatures skin tone. Dark green. The same as his own.

The mutants were so mesmerised by the sight that for a moment they failed to notice the other figures behind the first humanoid turtle. It wasn't until the dark green one suddenly jerked forward, pulling back as they all gasped with a smirk on its face, that they noticed that they were not alone with the mutant.

There were three other shapes coming through the mist toward them, all humanoid turtles, not close enough for them to tell much more than that and that they were not as large as the dark green one and that they all carried staffs of their own.

Donatello brandished his bo, mind working overtime, thinking back to a conversation he'd had with Raph and Leo only a few months previously, while working out their plans to free Mikey from Oruku Saki's clutches...

"Shredder's pet geneticist – remember him?"

"Like we could forget. Blood samples, skin samples, tissue samples – that guy was so fonda needles, he shoulda taken up acupuncture."

"But he vanished, years ago. He was on the mission under the city and the whole team went missing. Don't you remember how Ma- how Saki yelled?"

"Guys!" Don took a few steps back, wondering what else these new players might have in store. "Shredder's geneticist, the one that took all the samples from us over the years – I think these might be the results!"

"We've been cloned?" Raph couldn't take his stare from the one that shared his skin tone. Don couldn't be right, surely. Even if that thing did look a little bit like him.

Another turtle approached from the right, this one blueish-green, its posture less rigid than that of the first. Rather than the malicious humour of the first, its expression was more vacuous and yet there was something in its eyes, something that suggested malice.

"No way are those clones," said Mikey, sounding hurt. "I'm way better looking than that!"

"Not clones as such," clarified Don. "Genetic clones. Our genetic material was used along with some DNA from other sources to try to splice something else. In this case, these four."

"It doesn't matter how they came to be," said Leo determinedly. "Only that they're here and they don't look about to let us get through. We can take them!"

"Right on," replied Raph, leaping straight for the largest mutant.

Splinter held up a hand, trying to stop them. "Wait! There is something more at work here..."

No use. The turtles had already leapt into battle.

Raph charged at his cloned counterpart, refusing to be intimidated by its size. The creature grinned at him as he raised the sun and moon daggers – then sidestepped the assault, grabbed Raph by the arm and threw him. Across the courtyard. Raph landed on his shell and jumped instantly to his feet, facing down the creature but deciding to be more cautious this time.

What did they do, splice my DNA with a freaking ten ton truck?

He knew that if he could get in close enough he would be able to slice the creature open – it seemed to be flesh and blood after all and if it was, then it could bleed...

And then the creature raised its staff and a wall of flames sprung from nowhere, racing toward Raph. It was all he could do to leap out of the way in time. He somersaulted into the corner, stunned.

"What the hell?"

Mikey chose an air assault, jumping and going in high to his own counterpart, unnerved by the blank look in its eyes. There was no pupil in the orb, merely a solid blue-tinged white that didn't seem capable of sight. Yet its head followed his approach.

And then it rose its staff and a solid spout of water emerged from the flagstones at its feet, catching Mikey unawares and throwing him several feet in the air. As he tumbled off the spout, only his ninja training saved him from serious injury, allowing him to land with more finesse than anyone else would have done, but still bemused and worried about this new development.

Leo had dodged to one side and gone after one of the pair at the back, assuming that he would come up against himself – but as he drew his swords and headed for his quarry, he realised that the colour was all wrong. This clone was an olive green, standing at maybe six feet and clutching the staff in both hands. Not his clone. Donnie's.

For a split second he hesitated.

Then the clone brandished its staff and a gust of air hit Leo with hurricane force, knocking him head over heels backward toward the steps where Splinter still stood.

Donnie had gone for the last clone, noticing straight away that this was a result of Leo's genetic material – the colour of its skin could only be Leo – but at the same time realising that there was nothing much else of his brother within the creature. Whereas the Raph clone had seemed amused to see them and the Mikey clone had been grinning, this one was all business. There was a determination in its moves that told Don it would not toy with him but go straight for the kill. Donnie decided to do likewise.

He ran at the creature, bo raised as if he planned to swing it, but at the last moment he planted the staff on the ground and used it to vault into the air and kick the clone in the face.

Or at least that was the plan. As the bo hit the ground, earth from around the flags erupted, catching the weapon in a vice like hold and causing Don to fall backward rather than flip himself forward. Startled, he glanced down at the end of his bo, almost forgetting the enemy in front of him – until he glanced up and saw a fist heading his way. He rolled aside just in time.

"What the hell's going on?" shouted Raph, aiming the comment at Don, although he would have been happy for an answer to come from anywhere.

"These are mystical opponents," replied Splinter, not shouting but his voice carrying nonetheless.

"How can they be?" Don wrestled to release his bo from the grip it was in and avoid the crushing fists of the Leo-clone at the same time. "They're genetically engineered from our DNA and we don't have any powers like this!"

Splinter leapt forward, kicking the Leo-clone aside before it could crush Donnie, allowing him to retrieve his bo. "Perhaps the other source has the mystical abilities. I doubt that it matters. We must get through those that are in front of us."

"Right," said Mikey, dripping wet. "Any of you guys got a weak spot I can work with?"

"We all know each others fighting styles and weak spots," Leo reminded them. "Doesn't mean that they have the same ones."

"Worth a try," responded Raph.

Mikey raced over to the oversized Raph-clone, suddenly knowing what to do. "Hey! Ugly! Betcha can't hit the turtle!"

The Raph clone gave him a glare and aimed the staff at him. A moment later, flames leapt up in a circle around Mikey.

"Is that the best you've got?" Mikey jumped up, scaling the flames and landing on the other side of the circle. "That is so weak!"

A moment later a pyre erupted from the ground int front of Mikey, the sudden explosive force throwing him away.

"OK – that was pretty good," he admitted. "Guys, the weak point strategy isn't working!"

"Wait," said Raph, annoyed. "You think my weak point is you being annoying?"

"We can't get near them!" said Leo.

"There must be some way to fight fire with fire," said Don worriedly. So far, none of them had even laid a blow on the clones.

"Or magic with magic.." Splinter regarded the four clones. "I believe that conquering our mystic foes require a mystic weapon."

Leo nodded, removing the glove from his belt and the Sword of Tengu from the sheath on his back. Formerly merely a weapon, it began to glow with energy as soon as he plucked it out.

"Everyone get away from the temple – now!"

The four clones converged on Leo, who leapt into the air and flipped over them. As he landed, he directed a stream of energy from the sword at the clones, blasting them backward.

They got to their feet, the amusement that had been present in the Raph-clone and Mikey-clone gone. All of them now had nothing more than murder in their eyes. As one, they raised their staffs and conjured their elements in an attack on Leonardo.

Leo swung the Sword of Tengu, the most powerful blast he had ever manged to activate emerging from it. The energy beam easily cut through earth, air, fire and water, throwing the attacks back at them and hitting the creatures with their own powers, as well as the power from the sword.

The effect was startling. The four creatures fell, cowering on the ground, the staffs out of their grips. A cloud of smoke rose, from which it was impossible to tell. The air grew still once more and suddenly the courtyard was quiet.

Don approached Leo cautiously, watching the shapes of the four mutants through the smoke. "How is that even possible? How did he clone us and give them those powers?"

"I don't know Donnie," replied Leo, returning the sword to its sheath. "I don't think it's important right now."

Don looked like he wanted to argue, but chose not to.

"The sword of Tengu is a potent mix of science and sorcery," said Splinter calmly. "Perhaps these creatures are the same."

"Makes you wonder what's in store for us on the next twenty floors," said Don.

"Whatever's in store, we'll see this thing through to the bitter end!" Leo glanced at his brothers for confirmation, knowing he couldn't force them to go through with this – but they were all nodding their agreement.

"We're taking the Shredder down," said Raph. "Tonight."

"Payback time," added Mikey grimly.

Don spoke into his headpiece. "April – any luck finding us a stairwell out of here?"

"Best I can find is a private elevator on the west side of the building," came back the response. "But I can't tell if it reaches your floor."

Leo looked to the west, noticing a drape with the symbol for the water element on it. Pulling out a katana, he leapt toward it and sliced through the material, revealing the elevator behind.

"Found it!"

Don nodded and turned his attention back to the conversation. "So, where does this take us April?"

"Straight to the top boys." The smile in her voice was evident. "Straight to the top!"

The five entered the elevator and as it moved slowly upward, they exchanged looks. This was it. The final battle, one way or the other. This was the end.

"There is no turning back now," said Splinter, glancing at each of them in turn. So many years away from them... and yet, when they might have given in to the Shredder's ideologies, they had retained their good hearts, their sense of honour and the strength of their convictions. He felt privileged to be a part of their lives.

"No matter what happens today, I have never been more proud of you all."

There was a moments silence in the elevator. Then Leo inclined in a slight bow. "Thank you – Sensei."

Splinter smiled as Raph put his hand on the rats shoulder. Often he had dreamed of the time when they would once again be a true family and in this moment, he felt that they had recaptured it.

The moment was all too brief. The elevator came to a halt and Leo and Raph jumped to the ceiling, out of sight. One of their advantages came from no one realising that there were four turtles instead of two and they couldn't afford to lose that just yet.

The doors slid open and Don, Mikey and Splinter ran out, brandishing their weapons, ready for an attack. They had been expecting to find the Shredder up here, probably with Karai at his side and an army of Foot ninja to contend with.

In a sense, they weren't disappointed. But they had been unprepared for the sight that they faced.

Karai stood, sword in hand but not in a fighting stance. In fact, she seemed unconcerned by the arrival of the three mutants. She stood by the door to the doors that exited to Shredder's private courtyard and seemed to be all alone.

Donatello didn't trust appearances for a moment.

"Where's the Shredder Karai?"

The woman regarded him coldly. "You may wish you had not asked that question Donatello."

"You've got about five seconds to tell me or I'll make you tell me!"

In response, there was a loud crashing sound from the courtyard. The three mutants hesitated, taking a step back and Karai gave a humourless smile.

"You shall regret the day that you and your brothers betrayed the Foot."

"Um, Donnie?" Mikey glanced at the source of the noise. "Does that sound like – footsteps to you?"

Before Don could reply, the doors to the courtyard slid back, the faint mechanical hum lost beneath the metallic crashing sound emitted from without.

And the Shredder entered.

Or at least – it looked a little like the Shredder. It stood upon two armoured legs, but it had four arms rather than two, the lower two ending in hands with vicious looking metal claws on the end, the upper two with what appeared to be rotating blades. There was an array of weaponry on its back and it stood at least two foot taller than the Shredder ever had before.

But the real difference was located in the torso of the mechanical body. A small red – thing – that looked a little like an oversized, disembodied brain was operating it, a thing with ancient eyes and a malicious smile that revealed many small, sharp teeth.

It wore the Shredder's helmet.

Mikey took another step backward, nunchaku dangling limply in his hands. "What is that thing?"

The mechanical body clanked closer to them, its speed belied by its size. "You see me as I truly am Michelangelo. I am Oruku Saki, the Shredder, the one who raised the four of you – it has always been me. You see me as I truly am.. And I shall be the one to destroy the three of you."

"No." Donnie's voice was low and full of shock. "It can't be..."

"It can be," replied Karai, her voice as inscrutable as ever. "And it is. The Master is an Utrom, a being from another planet and one day he shall rule both that planet and this one."

"Over our dead bodies," snapped Mikey.

"That's the idea." The Shredder came forward and Don, Mikey and Splinter brandished their weapons, suddenly realising that Shredder had pulled the upset after all – and they were in for the fight of their lives.