This story was inspired by an AU-story-idea by my good friend nicollini and an awesome picture of Donatello she drew going with that idea. (It is used as a cover image here.)

Thanks a lot for asking me if I want to write the story to your idea, dear!

Chapter 01: Coming Home

Donatello stood up from his crouching position. He shook off the dust from his coat and readjusted the straps of his messenger bag and his backpack, before he wrapped the scarf tighter around his neck, followed by a quick tap on the goggles he had pushed back on his head to make sure they were still there. And then for the first time since he had entered this area he took a look around. A real look where he could actually see, not only looking for cover and making sure to make no noise and check every now and then that he hadn't been spotted. He was away far enough from the border patrols to not care about being spotted, and he had felt the urge to have a look around for quite some time now. He needed to see. Well, as much as someone could see in the darkness, but for Donatello that was enough.

He leaned on his staff, letting his eyes wander over his surroundings, taking in what he could make out.
The area was deserted. There was grass and trees and even a few flowers, but it just didn't feel right. Some of the plants' silhouettes made them look like as if they were from another dimension – which in a way – was true.

With a sigh Donatello allowed his memories of that day take over, the day when the Kraang had terraformed New York city and the surrounding area within a 40 miles radius. That day. The Day, how they called it now.

Kurtzman had informed them about a Kraang facility where he had thought they kept another clone of April, and Donatello and his brothers had decided to shut that place down. But when they had entered the facility, ready to blow it sky-high, they had been too late. The Kraang had already set up their machine to terraform the earth, using the clone's DNA to do so. And the moment they had arrived, they had started it.

Donatello could still feel the shock wave knocking him from his feet, he could still remember the silence following the explosion, this deadly silence, and then there had been this fog everywhere, containing these little droplets of mutagen. And after that, everything had sunken into total chaos.

He barely remembered what they had done afterwards, he remembered a fight, though, he remembered the screams of New York's inhabitants, he remembered the burning on his skin from the mutagen fog, but he had no idea what he had been thinking. All he had done had been reacting – getting out of there and back to the lair alive.

It had taken him quite a while to figure out what had happened when they had been back at the lair. He knew now that this last clone of April had been different, different from those they had destroyed at TCRI, but still, it had only been a clone. And that was the reason the mutation of New York City had been unstable. Some people had been turned into mutants, some plants had been mutated, but it still wasn't an environment the Kraang were able to survive in. On the contrary, this fog had killed a lot of them and destroyed their technology, forcing the remaining Kraang to retreat and hide. There had been rumors they were trying to reorganize now, but without their technology, without an ability to contact Dimension X there weren't exactly seen as a threat. Chasing Kraang hadn't been the Turtles' top priority since. They had had more important things to do – like surviving.

After the Day the government had declared New York City and its surrounding region to a prohibited area – first, because they weren't sure how to deal with this epidemic, back when they had thought this had been caused by a virus, and after that when they had been sure that there was nothing to be done, they had sealed it off from the rest of the country because they weren't able to get the situation under control. This was how "Area M" had been set up – "M" as in mutation.

In the insecurity of the first months some rich and/or lucky ones had been able to get out. Donatello ranked himself among neither. If he would have had a choice he would never have left New York. He would have stayed back and fought, keeping the city in an as normal as possible state. But he hadn't have a choice. He had had to leave.

When he had realized there wasn't much he could do and that he was stuck in finding a retromutagen, he had decided to seize the opportunity to be able to join other scientists and work together with them on a retromutagen. So he had contacted some scientists and told them that he had been a scientist himself before he had been turned into a turtle on the Day, but that he had some information on the mutagen. They hadn't asked too many questions about his past, fortunately. Although he would have been able to tell them that all his personal data had been lost during the riots and that he had cared more about saving his data on mutagen. But they hadn't asked about that. They had only been interested in his research on mutagen.

So he had left New York City for what had been planned to be a one-year-leave. But in the end it had been four years. Four long years he had been separated from his family. When the communication technology had still been working in New York they had sent each other messages nearly every day, but then the electricity supply had gotten worse and worse, and in the end it could have taken weeks to hear back from his family. He had sent them a message he was coming home two weeks ago, but he didn't know if they had received it yet. He wasn't even sure if they were still staying at their lair or if they had moved. All he could do now was going to their old lair and hope they were still there.

He looked into the direction where he knew New York City was. Four years ago, before the Day, it would have stood out a mile with its glittering lights in the dark, its illumination as bright as day, the city that never sleeps. But it was dark now, its light a distant dim glowing, pathetic as compared to its brightness of old days.

Donatello had seen satellite pictures. He knew how dark the city was now at nights, what kind of creatures were roaming it in the darkness, what kind of people. New York City, the city that never sleeps, was sleeping now at nights. No, sleeping was wrong. Donatello could imagine the tension among New York's inhabitants when night fell, when all that was important was surviving. No, New York wasn't sleeping. It was wide awake at night, paralyzed by shock.

Donatello took a deep breath. And even now that he knew that, he just hadn't been able to stay away any longer. He and the other scientists had been working on a retromutagen for four years now. And they hadn't been able to find a cure. They had used April's DNA, going through the sequences again and again and again, but it just didn't work. Maybe it was because it hadn't been exactly April's DNA the Kraang had used to mutate Area M, at least that was was Donnie was forcing himself to think. Maybe the answers he needed were waiting inside the city walls.

It was the only thing that made it bearable for him to come back with empty hands because practically, he hadn't failed. He was just still working on it.

The grip around his staff tightened as he straightened up.

"Okay, then," he mumbled as he moved on, "it's time to go home!"

Michelangelo was searching his way through the sewers' tunnel. He hated it when he was on night duty and the alarm was set off. According to the records it only was a minor problem, so he didn't have to call for his brothers. And most probably it had just been a raccoon or a rat that had set off the alarm. It had been like this the last few times. And never ever would he ask his brothers for backup again if he wasn't sure he really needed their help. He had done that like three times and when it had turned out that it has only been a rat, they had made fun of him. So he wanted to be sure this time.

Fun… They weren't having much of it lately – or in the past four years. He had had to learn how the security system worked and how to read the records. He now was decent at it, but what would he do if he ever had the chance to play video games all night again! But electricity had been short all this time, and they couldn't risk using it for video games or the TV. Their only way of communication was the radio. That was where they got the information from if they needed to wear face masks on a day when they went topside or not, depending on the wind conditions and the pollination from the plants in Central Park.

Central Park had been turned into a jungle on the Day, getting hit by more of the mutagen fog than the rest of the city, a jungle full of mutated plants and mutants of all sorts. And after some time they had realized the pollen of the mutated plants made people mutate slowly, bit by bit. That's why they had to wear face masks from time to time. Most of the people in New York City had a face mask handy, and those who hadn't either tried only to go outside when it was safe or did everything to get a face mask. Michelangelo had seen people fight over face masks.

Actually, he had seen people fighting over all kind of things – clothes, food, fire wood.

He sighed. No, there hadn't been much fun lately. And he was afraid there never would be.

And with that thought he went into stealth mode as he got closer to the place where the alarm had been set off.

And then he stopped, watching closely what was there in the tunnel in front of him, waiting for the right moment to strike. The shadowy figure there obviously was no rat or raccoon, but seemed to be a man, but Michelangelo was sure he could handle this one alone. He darted out of his cover, gaining speed as he ran for the shadowy figure. He practically crashed into it, pressing it against the wall.

He wanted to ask this intruder what he was doing here, the question already waiting on the tip of his tongue, but he didn't have a chance to pronounce it, because at that exact moment the intruder spoke up.

"Hello, Mikey," a voice said, an all too familiar.

Michelangelo drew back a few steps, his eyes widening in surprise.

"Donnie?!" he asked disbelievingly.

"The one and only," the other mutant said and stepped into one of the dim stream of lights falling through the street grate above them. "By the way, what took you? I set off the alarm seven minutes ago. I thought you might have move…oof!"

The last word turned into a gasping sound as his brother wrapped his arms around him and hugged him so tightly that it felt like he was pressing all the air out of Donatello's lungs.

"Guys, guys, guys!" Mikey called out as he entered the lair. "Guess what I found!"

"Another raccoon, Mikey?" Raphael asked back as he turned away from the practice dummy and faced his brother while Leonardo who had been preparing their dinner in the kitchen entered the living room.

"No!" Mikey replied and beamed at his brothers. "This!"

And with that he stepped aside and thus revealed Donatello entering the lair.

Leonardo's and Raphael's jaws dropped and their eyes widened.

"Hi, guys!" Donnie greeted them with a wave of his hand.

"I can't believe it!" Leonardo called out and marched over to his brother to hug him. "You're back!"

"Sure am!" Donnie said as he hugged him back with a smile.

When they let go, Donnie found his second oldest brother standing close to him. The hothead hesitated, not sure what he should do now, if hugging his long gone brother would make him lose some coolness points, but then he decided he didn't care and roughly wrapped his arms around his brother. Donnie couldn't help but chuckle silently as he hugged him back.
When Raph let go, he immediately stepped a few steps back.

"Didn't think you'd ever show your face around here again," he mumbled as he eyed up his brothers, the usual grumpy look back on his face as he folded his arms over his chest.

"And still, I'm back," Donnie replied with an insecure shrug.

He took a moment to eye up his brothers. They had changed over the past four years! Michelangelo had grown and thus had left Raphael being the smallest turtle around. But their youngest brother had kept his chubby cheeks which still gave him that childish look.

Raphael seemed to have spent even more for training, his body even more shaped by muscles now.

Leonardo had grown as well and even though he still had well-developed muscles he looked more slender now.

And they all had a more mature look on their faces, their eyes looking earnest and thoughtful, although there could still be some mischief detected in Mikey's eyes, and this somehow relieved Donnie a bit. Although his brothers were grown-up and earnest, but they weren't hopeless.

And then he thought of how he must look like to his brothers in his clothes and luggage, his staff resting in the holder of his backpack. He wasn't even wearing his mask. He still had it, of course – it was in his backpack – but it hadn't fitted the "former human scientist"-appearance he had been going for. Neither had his staff, so he had told people it was just a walking staff. He had lost weight over the last years and hadn't spent not as much time training as his brothers obviously had, so even if he still had some muscles, on the whole he was scrawnier than ever.

"Where's Master Splinter?" he finally asked.

"Master Splinter is out to get some supplies. He won't be back before morning," Leo explained.

"I see," Donnie said. "And April?"

The young woman had moved in with the turtles after the Day. They had decided it would be safer for her if she wouldn't live alone. Her aunt had been out of town on a business trip at the Day. Donnie had checked on her when he had been out of Area M. and she was okay. He had told April via e-mail and it had made this whole situation a bit easier for her now that she knew her aunt was safe.

"She is out to visit her fath...," Leo started, but was cut off by a surprised outcry.

"Donnie?!"

Donnie turned around to set eyes on April standing lair's entrance.

"April!" he greeted as she passed through the turnstiles and ran over to the mutant turtle, wrapping her arms around him.
With a smile Donnie hugged her back.

"You're back," April mumbled as she pressed her face against his plastron.

"I am," Donnie replied.

When April's grip on him loosened a bit, he shoved her at arm's length to be able to have a proper look at her. April had grown a bit, her whole appearance had become more mature, though she was still wearing her trademark outfit composed of her yellow shirt and her jeans shorts. This wasn't the teenager he once had known, this was a woman. And just like his brothers the look on her face had turned more earnest now.

This was what catastrophes did to fun-loving teenagers, Donnie thought – make them grow up fast, maybe too fast.

"How have you been?" he asked April. "And how's your father? Leo said you've visited him."

His eyes had been so fixed on April he hadn't seen that his brothers had gestured at him to stop.

April stiffened and she shot a hurtful look at Leo.

"No, April, I didn't say that!" Leo defended himself. "I was interrupted! I couldn't finish the sentence!"

April looked back at Donnie, tears glistening in her eyes as she shook of his hands and stormed out of the living room.

"April!" Donnie called out and wanted to follow April, but Leo held him back.

"I'm taking care of this," he said and left for April's room.

Donnie looked at his two other brothers helplessly. Mikey had lowered his eyes uneasily, so he turned to Raph, hoping to get some answers. His brother tried to avoid his look for a moment, but then he gave in with a growl.

"Her father died," he said.

"What?!"

"You remember how we put a tracking device on Kirby?"

Donnie nodded. Of course he remembered. It had been his idea, so April could keep better track of her father.

"Well, thanks to that device April had soon found out which places a human turned into a mutant bat preferred. She checked on him every day on the tracking device's records, and even visited his favorite places now and then. He seemed to get used to her again and didn't take flight when she was near. So things were going pretty well," Raph explained. "But about a year ago she realized the tracking device hadn't been moving for a few days. She thought it would have fallen off like it had before. So she went there to get the tracking device back and then look for her father at his favorites places to put it back on on him. She sure wasn't prepared for this." Raph took a deep breath and lowered his eyes. "The tracking device hadn't fallen off. It was right there where it belonged. Her father hadn't moved because he was dead. We got there the same night to salvage the body. We don't know what happened to him, but by the way how battered his body was we think that some mutant haters had caught hold of him."

Donnie lowered his eyes. He had heard of these mutant haters. They made the mutants responsible for what had happened to New York.

"I see," he mumbled.

"She was visiting his grave today," Mikey explained.

With a determined look on his face Donnie left the living room. He needed to check on April.

When he had reached her room, Leo was leaving it.

"Is she better?" Donnie asked. "At least a bit, I mean."

Leo frowned at Donnie. "I guess, but Donnie, I don't think that…"

Donnie didn't let him finish the sentence and entered April's room.

Leo just shook his head. What was it that people kept cutting off his sentences today? And with that he left for the living room again.

"April?" Donnie asked. He scanned the room and found her cowering on the floor near her bed. She had hugged her knees and was hiding her face. She didn't look up when she spoke.

"Please leave!" she said, her voice still sounding a bit tearful.

Donnie hesitated for moment. He wanted to make her feel better, he wanted to be there for her, especially when he realized her body was shaken by another crying fit. He even took a step into her direction, but then he stopped. He realized that he just couldn't force his comfort on her. That would make everything even worse.

"Okay, if you really want me to, I am leaving," he said then, but he didn't move immediately to give her the chance to hold him back.

"I really..want..you to!" April gasped out.

"Okay," Donnie said again, and then he turned and left her room.

After telling his brothers that he needed to rest a bit, Donatello entered his room. When he looked around he realized that Master Splinter had kept his word. His sensei had said that his room would always be waiting for him, just like the way he had left it. And yes, his room looked exactly the way he had left it. He wondered how his family had been able to clean it as he realized that his belongings he had left behind back were on their usual places because the room actually looked pretty clean.

He took his staff out of its holder on the backpack and placed it on the floor near his bead, before he put down his messenger bag and the backpack as well. He knelt down and opened the backpack, rummaging it for a moment before he took his mask out. With an earnest look he put it back on carefully. The cloth on his skin felt so familiar, so normal as if he had never taken off his mask in these four years.

With a sigh he slid down on his bed on his carapace and crossed his arms behind his head.

Yes, he was back home. He had waited four years now to be able to think that. Four long years his thoughts had always found their way back here, and finally he had been able to follow them. But why did he feel then as if he didn't belong here anymore?