For the past 24 hours, he did nothing but type on his keyboard, going over code after code. Looking over every possible equation he could think of, trying to find something anything that would give him the answer to the question he sought the most.

Donnie didn't sleep, he didn't eat, all his time was spent on that computer, he stared at the screen until his vision blurred, probably from lack of sleep or lack of food or both. But even then he kept working because working helped him focus, working helped distract him from reality and right now he wanted to be as far away from reality as possible.

That was until Leatherhead physically dragged him away from his desk, stating to him that he couldn't continue to do this and locked him out of his lab until he slept and had a decent meal. Donnie didn't go quietly, he struggled and protested, he needed to keep working, he had too. "Leatherhead! C'mon, you know I'm close to a break through, I can't stop now!" That first part was an obvious lie, he was no where close to a cure then Leatherhead was. Even with their combined intelligence, they still weren't enough to figure it out.

Leatherhead merely shook his head, not believing his fib for even a second. "Go rest, my friend. I'll continue our work until you've done so." And with that Don was officially band from his own lab. And without something to do, Don indirectly being forced to—

In the distance, a muffled growling could be heard, followed by a faint thumping sound coming from inside of the contained that M—

Donnie shut his eyes and clinched his hands. Without any else to do, he began wondering aimlessly around the lair trying to find anything to occupy his time so that he wouldn't have to think about what everyone else was thinking about. It seemed like his legs were working on autopilot, for soon he was in Raph's room, looking inside he found that his brother in his hammock with the covers pilled over his body. Whether Raphael was sleeping or sulking, Donnie had no idea. His feet then took him to Leo and Master Splinter, whom, instead of the dojo were calmly meditating on the scaffolding of their new lair.

Finally his feet laid him into the kitchen, he remember Leatherhead's words about him needing to eat. Food and rest, that was the only way he was getting back in his lab to continue his work. The last thing he wanted to do was eat anything and sleeping would only cause him more harm then good. He's been on countless receiving ends from one of his all nighters, and they were horrible to get through, it was like going through withdrawals, only it was ten times worse because not only would his mind and body refuse sleep and sustenance but they were also at times be at war with one another.

Leaving Donnie in a terrible state of fatigue but unable to rest and his body aching from lack of food but too nauseous to keep anything down. His only option was too continue working, but Leatherhead was far too smart to be tricked or manipulated. And even if he could continue his research, he'd most likely collapse anyway, even he had his breaking point.

So he was a turtle without any luck, walking out of the kitchen, he repeated the same steps as before only this time he noticed some things had changed. Raph had since moved from his room and was now hitting away at his punching bag, most likely trying to let off some steam without having to go to the surface, while Leo and Splinter had completed their meditation session but Leo seemed to be in low spirits, for he watched as his big brother's shoulders hunched upward, becoming stiff and rigid, relaxing only slightly when their father placed a gentle hand on his shoulder. Don turned away from the scene, the sight of it made his own shoulders stiffen and a feeling bubbled up in his chest that he had to forcefully choke down, he continued walking.

All this aimless wondering made him feel like such a child, like when he was 7 years old, and one of his inventions malfunctioned and zapping Raph with an electrical discharge straight in the face, almost permanently damaging his brother's eye. Splinter had, rightfully so, grounded him from all his gizmos that he had held so dear to him back then. So with nothing to do little seven year old Donnie had wondered helplessly through the lair, clueless on what to do. And now here he was again, age 18, doing the exact same thing. Only difference is that he wasn't in trouble nor was he grounded, well at least not from Splinter.

To be honest, he almost wished he was, he wanted someone anyone to yell at him, scream at him for what he'd done, tell him that everything that happened recently was on him.

But no one did this, no one except himself.

When his legs finally stopped, Donnie was not surprised at all when he found himself in front of the tank that contained the very person they were all trying so desperately to save. Don watched as though piercing red eyes stared directly at him, the snarls and roars increased ten fold now that his brother was face to face with someone. He felt his heart ache, it clinched in his chest. The monster brought its jaw closer to the glass and roared it's loudest yet, fogging up the glass.

His little brother, for a moment, was distorted from view. The only thing that Don could see in the glass was his own reflection. And to say he looked awful would have been an understatement. His eyes were bloodshot and sunken in, his skin looked paler then it normally does. Reaching a hand out, he placed it on the glass, moving closer completely stunned by his own appearance. At how horrible he looked, how broken he looked. How was he suppose to save M... Save his brother when he himself, already appeared to be on death's doorstep as well? He was suppose to be the logical one, the smart one, he's suppose to have all the answers, how could he have let things escalate so quickly?

Then a giant fist pounded on the glass, causing Don to up back in surprise. The fog faded away, revealing his brother again. Mindless, feral, there was nothing left of him, nothing left of their beloved Michelangelo. Donatello felt something inside him, snap. His mind and logic disappearing at the exact same time. His nails dug into his palm, seeing nothing but red as his fist connected with the glass hard, he reeled back he did it again.

And again

And again

On the fourth strike he felt someone grip a hold of his wrist and pulled. His instincts took over and he fought against the force that was holding him back. Distantly, he heard voices, though he couldn't really make out what they were saying, his thoughts were too chaotic to hear anything, it was like his mind was in a sea of static, leaving him deaf and broken with guilt.

Then finally, finally, he was able to break free.

He turned around so fast his vision blurred, blinking his eyes still storming with anger and chaos, Donnie saw his brothers standing there. Both Leo and Raph looked concerned and shocked, they stood there panting. And after a few seconds Don realized he was panting too, his breathing in synchronization with them. They all stood frozen to their respective spots, he could feel his body vibrating, trembling.

Leo, slowly took a small step forward. "Donnie—"

Donnie instinctively took a step back.

Then Leo held up his hands in defense. "Don, hey. It's me." Leo's voice tried to stay calm as he took another step forward. "It's okay, Donnie. You're gonna be fine, Okay? It's okay."

"You're fine, Mikey"

"You're gonna be fine. I promise."

His heart ceased in his chest and let how a deep, gut wrenching howl, "NO!" Because it wasn't okay, it wasn't fine. He wasn't fine and neither was their brother. Why couldn't they see it, why couldn't they understand? Their youngest was dying and there wasn't anything they could do about it, there wasn't anything he could do about it. "It's not! He's not, I'm not! This is all my fault!" Tears blurred his vision, a choked sob escaped his throat, "I told him he was going to be fine, I said that cut on his arm was nothing to worry about!"

"We all thought he was gonna be okay, Donnie. That doesn't mean what happened is solely on you."

Don shook his head, Leo wasn't hearing him, wasn't listening to him, they didn't understand.

Why?

"But I should have known better." He should have known better, after all he's seen and dealt with he should have realized that his brother wasn't gonna be okay. How could he have been so foolish?

Master Splinter who was now standing besides Leatherhead a few feet away, was staring at him, his eyes holding concerned but also a will to understand. "My son, no one blames you for Michelangelo's condition."

Don knew this, he knew this and that made it all that much worse. Knowing that Leo and Raph didn't blame him for what happened to their brother, knowing that they still cared about him as always, he didn't deserve such forgiveness, it was all too much to bare. "Well you should. Please, I deserve some sort of punishment."

For all his mistakes, for all his miscalculations and screw ups in the name of science

Everything that he has done and possibly will do in the future

Donnie needed someone to tell him it was all his fault, validate all his thoughts, so he didn't feel like he was slipping away from reality, like he already slipped away from his sanity. But no one did, not a single member of his family announced that he was at fault. "My friend, you are suffering from severe sleep deprivation and hysteria, you must calm down." Leatherhead along with Splinter took a cautious step forward as did his brothers.

"Donnie, let us help you."

"C'mon bro."

"My son, please."

They were all talking at once, or at least that's how it sounded like in his head, their voices were mixing and combining into a hazy mess of muffled and distorted sounds. Donnie couldn't focus, could considerate, he grasped his head in agony, it felt like someone was slipping his skull apart, his ears felt like they were going to exploded from all the pressure he felt. The entire ground felt like someone pulled a carpet from underneath his feet and he couldn't gain his footing.

And for the first time, Don wanted to run away, he want to turn and run in the opposite direction of his family.

His family that only wanted to help.

He realized, that maybe that's what the other Michelangelo had said when he accused him of abandoning them, the one from that future Drako sent him to. Body shaking, lungs heaving, breathe hitching, Donnie back away from them, he back away and away until his shell collided with something hard.

Then a loud, muffled thump could be hear abruptly behind him, another yelp of surprise escaped him, he wiped around and was face to face again, with Michelangelo

It was like someone took of his rose colored glasses and he was finally able to see, see the reality that was before him, the possibility that he— they had failed their littlest brother, that Mikey was lost to them in this monstrous form and would soon be lost to them completely as the body continued to break down And what he saw, that knowledge destroyed the last of his resolved.

His heart broke within seconds, it bleed agonizingly, as it lay before him shattered into pieces. As a wail of utter despair was ripped out of his throat, "MIKEY!"

He fell to his knees, his heart shattering from the amount of pain it was in, from the guilt he felt. He couldn't think straight, he could do nothing but chant his brothers name over and over again in his head, a desperate plea.

Mikey

Please...

His brother, his only little brother that meant everything to him, would soon be lost to them all, to him.

How was he suppose to accept that as reality, how could he have failed him again? He vowed he wouldn't ever fail his brother, abandon them, like that other Donatello did. And yet, here he was, failing Michelangelo, while he and the rest of his family had to watch as he deteriorated right before their eyes.

"Mikey... I'm sorry..."

Mikeymikeymikeymikey

This was all his fault.

Donatello didn't usually didn't get nightmares, like his brothers did. He remembers countless times each of his brothers jolting away, trembling and so filled with fear, when they all use to share one room as kids. Raph would remain perfectly still, suffering in silence, his heart pounding in his ears, as he refused to let the tears fall. Leo, with silent tears on his cheeks would debate either crawling over to Master Splinter for comfort or watching over his still sleeping brothers, as the natural protector that he was, and Mikey would wake up sobbing so loudly he would wake everyone else up and they'd all have to spend the next couple minutes holding him and trying to calm the youngest down. But Donnie, didn't really have nightmares growing up, because he really didn't have anything to fear back then, he always knew that Sensei would keep them all safe.

Even afterwards when they all got separate bedrooms, his brothers still had bad dreams. But not Donnie, at least not until Draco sent him to that portal to that alternate universe. Where Shredder had taken over the entire world, where Casey and Splinter had long since died and his brothers...

His brothers—

Ever since then, he's done his best not to fall asleep.

Drinking excessive amounts of coffee, working in his lab with hardly any breaks. He had a system, a routine, but even he had his limits, limits where he'd slip up, drift off into dreamland only to be awaken seconds later, in the very middle of the night by a nightmare. They twisted and morphed, swirled around in his subconscious. A barren wasteland, April wrinkled and tired, Stockman and Hun fused together. And then, blood. God, so much blood as the Karai Legions ripped through Mikey, his scream echoing through the battle field, everyone stopping dead in their tracks from complete and utter shock. Then Karai herself while the eldest' back was turned, struck down Leo and then second later did the same thing to Raph in a fit of rage. And then it was just him, him with his brother's corpses, failing them... because he had survived and they didn't.

Because he was alone.

A silent scream tore itself from his throat as he jerked up, almost tipping his chair so far backward both it and him had almost crashed to the floor. That was, if it hadn't been the obvious hand that steady the back of the chair, keeping him from falling. Turning, he saw Mikey standing there, looking confused and concerned, "You okay, Don?"

Taking a few seconds to compose himself, Donnie let a shaky breathe escape him. "Mikey..." His heart still hammered in his chest, he closed his eyes and breathed in once. "Why are you—?"

Mikey smiled at him, he turned and revealed a display of food. Homemade soup, crackers, and Donnie's favorite kind of soda all neatly place on the serving tray. "You've been in here so long, working so hard, I thought I might bring you some dinner."

Donnie blinked, his eyes checking the time. 6:47 pm, has he really been here all day? "I hadn't realized. I thought— I still had time too..."

Mikey simply waved him off, with a smile, gently setting the tray on Don's lap. "No worries, Donnie. I know you've been stressed out lately. What with all the nightmares lately."

His heart turned to ice in his chest. "How did you—?" He had been so sure his had kept it all a secret, he hadn't want to worry his family, or tell them for fear of anger or resentment, of fear of their own for this possible future.

But Mikey merely laugh, "C'mon, Donnie. I know I'm a goofball and that I'm not as smart as you, but I'm not stupid. I know how a person looks after they had bad dreams. It's not that hard."

Don's eyes, widened in horror. "No, no! That's not what I meant, I don't think your stupid." The last thing he ever wanted Mikey to think was that he was stupid. Because Donnie was sure that the reason why Mikey had turned so distant and cold in that future was not just the horrible life he had lived but from resentment, from the anger he had towards the family that saw him as an annoyance half the time. "I just thought it be better if you all didn't know."

"What? Because you feel like it's your fault we all died in that weird dimension Drako sent you?" Once again, Donnie blinked, jerking his head up in shock he stared at Mikey, completely dumbfounded. But Mikey simply continued, "Kinda hard not to hear you, when you talk in your sleep, Don." Donnie watched as his little brother's face turned completely sober, and serious. "You know we'd never blame you, right? What happened there wasn't your fault."

"Yes, it is." Don said venomously, the anger boiled in his heart.

"No, it isn't."

"Yes, it is."

"I can do this all night, Donnie."

"Michelangelo."

"Donatello."

He glared at Mikey and Mikey glared right back, wavering not even the slightest bit.

Then something in his heart just gave way, and he sighed in defeat, gripping the sides of the tray with both hands. "How can it not be, Mikey? After all I saw, after witnessing so much pain and seeing you all... It has to be my fault, it has to be. It's the only thing that makes sense. The only thing that feels logical, the knowledge that I failed you guys. What more proof do I need that it's no one's fault but my own? "

Mikey's face morphed into one of matched sympathy and sadness. "Aw Donnie." Then Mikey grabbed the tray from Don's still clinched hands and knelt down in from of him, "Look," He said gesturing his left arm forward, presenting it to Donnie like some type of evidence. "See, it's still here, I'm still here, and so is Leo and Raph and Master Splinter and Casey. We're all still here, Donnie. We're alive, that's all the proof you need, everything's okay."

Don looked down, looked down at the very arm Mikey had lost. His own hands sought it out and grasped it, desperately. It was solid and real and there, right before Don's eyes, then he looked up and saw that same smile on Mikey's face. That same signature smile that could light up a room with it's mere presence, that could warm even the most coldest of hearts. It was a smile that Donnie fought so hard to protect, what they all strived to keep alive.

Gently, he reached a hand out and cupped his baby brother's cheek, the action made Mikey smile even wider and Donnie felt the edge turn up and form under his finger tips.

He hadn't realized he started crying until a sob tore itself from his throat and he launched himself forward, wrapping Mikey in a crushing embrace. He clung to his baby brother, breath hitching as he sobbed unashamed. Cried out all the pain and dark emotions caused by the future he had been forced to witness. Because the thought of Mikey not being Mikey, was a thought that horrified him.

"I love you..."

Mikey let out a content sigh, returning Don's hug just as fiercely. "I love ya too, Donnie."

His heart still ached, his mind still flashed to the future he'd seen, but having Michelangelo here, by his side, just as understanding and loving as he always was, made it just a bit more bearable. He pulled Mikey closer to his plastron, eyes closed tight, he babbled out, "Please, don't ever change... Please... just... stay as you are, I won't ever get annoyed again just... please."

"I won't change, Donnie. I promise. I'll always stay me."

Faintly, ever so faintly, he felt multiple arms wrapping around him, encasing him in a warm cocoon of comfort, and keeping him just inches from falling through the abyss that was his shattered sanity, just dangling helplessly. Distantly, he heard Leo's voice, muffled through all the static and white noise in his ears. "It's not your fault, Donnie."

Yes it was, but they didn't understand. Didn't understand the extent of this, how bad this all truly was.

It was all his fault. This was so much worse then before, so much worse then that damn alternate dimension. If only he had realized, if only he ran more tests, if only, if only—

He was suppose to be the smart one.

How could he have not thought of the possible fact that getting injured by another mutated creature would have a secondary reaction, how could he have been so utterly stupid? How could he, simply bandage the cut without doing further testing? He looked at Mikey, who was rightfully scared and upset, and told him he would be fine.

Did you know Mikey? Even back then, that something was wrong and I just didn't listen?

Donnie couldn't cure him.

Admitting that made him choked, his harsh sobs echoing around the room. They were out of options, they were running out of time,

They had nothing, now all that Donnie had left was guilt. How was he suppose to fix this? How was any of them suppose to fix this mess?

No one answered.

Ohhh boy, sorry this one took me so long to post, I had no access to a laptop for the past couple of days. But I was finally able to finish and I am really proud of this chapter? I've always really loved writing for Donnie whenever I write a story for TMNT. Him, Mikey and Leo have always been so fun for me to writing about. And this I put Don through the ringer, but I knew from the get go that he was gonna be the most effected with what happened to Mikey.

And while I stressed a lot on the fact that Donnie feels like everything is his fault, at the center of all that guilt and fault, lays a broken boy, that loves his baby brother very much.

Anywoo, a penny for your thoughts? Feedback is always welcomed and appreciated in comments down below, if you all have the time, and I'll see you all soon.