Summary: When Donatello gets accidentally sent through a Kraang portal, he ends up in an alternate universe that may be his world's future — a future in which he has been gone for thirty years, his family has been torn apart, and the entire world has fallen victim to the Kraang-Foot takeover.

This is a TMNT 2012 SAINW story, so I incorporated the Kraang pretty heavily. While working on this story, I rewatched several episodes of TMNT to get the Kraang tech as accurate as possible. Watching several episodes back-to-back, I discovered a lot of inconsistencies in how the Kraang technology works. So I chose what made the most sense to me and embellished a little in some places

Chapter 1

Donatello yawned as he stared at his attempted retromutagen samples under the microscope the guys had managed to swipe from the lair. Something about the Kraang's "perfected" mutagen wasn't reacting the way he expected it to while he was trying to create an antidote to reverse its effects, and he was beginning to become frustrated by the constant setbacks in his work. It wouldn't matter if they managed to find Karai if he didn't have a retromutagen to make her human, and they certainly couldn't turn back New York City's residents, wherever they were, without it.

For the most part, his family tried not to press, but he could sense Leonardo's anxiety behind his brother's mask of patience. Worse, yet, was the sad look Master Splinter, April, and Casey all got whenever they thought about their missing mutated family members. And to add to it, his brothers were practically itching to have something to do. In the short couple of years that they had been allowed above ground, they'd been active protectors of the city. They didn't know how to just wait while the entire city remained under the Kraang's control.

Tonight, they — with the exception of a TV-binging Michelangelo in the pizzeria's dining area — were currently nearby studying maps of the city, discussing were the Kraang seemed to be centralized and where they had seen Karai. They all knew that it was not necessarily that helpful, but without Donatello's retromutagen, there was little else they could contribute at the moment.

April had apparently caught his yawn, because she smiled warmly at him and stepped away from the huddle around the maps. "Coffee, Donnie? I just put on a fresh pot not too long ago."

"Please," he said appreciatively.

As she went to the coffee-maker at the front counter, Raphael stepped away from the group with a frustrated growl. "I'm sick of all this waiting! When are we going to get out there and do something, Leo?"

"We aren't ready, yet," Leonardo said.

Raphael rolled his eyes. "You mean the retromutagen's not ready. We're sitting here, pretending we have something do while Donatello takes his sweet time mixing that crap."

Donatello sighed and put down the beaker and test tube filled with substances he had been about to mix. Leave it to Raphael to be the one to outright blame Donatello for his restlessness.

"Raphael, perhaps we have to review your lessons in patience," Master Splinter scolded.

"But I've been patient, Sensei. We've all been patient." He glared in Donatello's direction and crossed his arms over his chest. "When are you going to be done with that retromutagen, Donnie?" he demanded.

"I'm doing the best that I can, Raph," Donatello muttered.

Raphael scoffed, shaking his head as he looked away. "Yeah, well, if saving New York is in your hands, we're all doomed at this rate."

Leonardo sighed into the hand that now covered his face in exasperation. "Can we just stop fighting right now? It's time for patrol, anyway."

Donatello looked down at his notes. There was no way going on patrol would help him get this done any faster. Besides, as exhausted as he was, the guys would probably be better off without him tonight.

"Don't listen to him," April said as she came to stand beside him. She set the hot coffee mug down on his work table and offered him a sympathetic smile. "He doesn't really think it's your fault. He's just being a jerk, as usual." She directed that last comment over her shoulder to the hotheaded turtle, who rolled his eyes and slid his sais into his belt.

"But it is taking forever," Donatello said. "And I just can't seem to get the formula right."

"I know you can do it, Donnie. We all believe in you. You'll figure it out, and that's more than anyone, Raphael included, is doing."

"Do you have something to day to me?" Raphael growled from the dining room.

"Nothing your eavesdropping hasn't already overheard," April replied.

"Oh, snap!" Michelangelo laughed before crying out at the fist Raphael threatened to pound him with.

Master Splinter approached Donatello and April. "My son, why are you not preparing for patrol with your brothers?"

"I just have so much work to do, Sensei," Donatello explained. "Can't Casey fill in for me, just this once?"

"I'm totally game for that!" Casey agreed excitedly.

Splinter gave the teen a dubious look. "I do not think that would be wise. It is hard to focus when you have not taken the time to clear your mind. Perhaps the fresh air will allow you clarity when you resume your work tomorrow, after a full night of sleep."

Donatello looked down at his cup of coffee in shame. His father was obviously not a fan of his replacing sleep with caffeine, but they were pressed for time. What else could Donatello do?

"Are you sure?" Donatello practically whined.

"I am. Now go. Your brother is most impatient tonight." He squeezed his son's shoulder reassuringly. "Pay little attention to his complaints. It is difficult for him to be confined to such a small space. That reflects poorly on him, not you."

Donatello sighed and reached for his bo staff. "Hai, Sensei."

The turtles kept to the rooftops that night as they tailed a group of five Kraang droids below them on the streets. Not long after they started their nightly search for Karai, they had heard a young girl screaming nearby. By the time they had located the source of the commotion, they had found the Kraang droids carrying two unconscious and unmutated humans — a woman in her early twenties and a middle-aged man — toward some location.

Raphael, predictably, had wanted to dive in and smash the droids, but Leonardo and Donatello demanded that this was their opportunity to find out what the Kraang had done with the rest of New York's population. Apparently, they were still wrangling a few human stragglers.

This was what led the turtles to their present situation, staring through the skylights of a warehouse that had apparently been taken over by the Kraang. Alien technology filled the space below them.

The humans were dropped unceremoniously on the ground as the five Kraang droids joined twelve more in the warehouse.

"Kraang has located two of the humans that are the ones known as 'leftover,'" said one of the Kraang from the street.

Another Kraang examined their prize. "Kraang has done what is known 'excellent work.'"

"It is now time to mutate the humans that are the ones known as 'leftover' for transport."

Several Kraang were at work on the computers. Suddenly, a machine filled with mutagen lit up. A second later a portal device rose into the air and opened a portal, presumably to Dimension X.

"This is bad, dudes," Michelangelo said warily.

"Can I smash 'em now?" Raphael asked Leonardo.

Leonardo pulled a sword from its scabbard and nodded. "Let's go!"

Donatello lifted the skylight window and allowed his brothers to slip through before silently following them. They crept through the shadows along the sides of the room until Leonardo gave the signal to strike. It wasn't a moment too soon, as a Kraang droid set the young woman on the platform for mutation.

"Booyakasha!" Michelangelo cried as he used his kusarigama chain to pull the unconscious woman out of harm's way.

"It is the ones who are known as the turtles!" one of the Kraang droids announced before Raphael's sai impaled the robot head.

"Get the people to safety!" Leonardo ordered.

Donatello used his naginata blade to decapitate a droid that attempted to take the man. The Kraang inside crawled out, hissing and squealing. He reached down to feel the man's pulse, which was strong, to his relief.

Michelangelo was laughing as he leaped around the room, evading attack after attack. His cry of "Can't touch this, Kraang!" was quickly followed by a shout of alarm, as a Kraang laser nearly took off his head. He back-flipped onto one of the Kraang computers and suddenly more portal devices were opening around the room.

"Mikey!" Raphael grunted as he flipped a Kraang over his shoulder and into one of the portals.

"Whoops! My bad!"

"Donnie, watch your back!" Leonardo shouted in time for Donatello to duck and swipe another Kraang droid's feet out from under it. Unfortunately, a laser fired at his feet, causing him to misstep, and before Donnie realized what was happening, he was tumbling backward through the portal.