Upon April's and Kirby's return, everyone helped them unpack, bringing Leo's equipment to the table－ everyone except Raph, that was. Raphael still hadn't returned.

Even after everything was inside and they were unboxing all the equipment, Mondo still glanced at the door.

"We brought everything in," Mr. O'Neil clarified when he saw Mondo looking.

Mondo just nodded.

The equipment hadn't been what－or who－ he'd been looking for.

More than once, he'd been told he was insensitive, by acquaintances, by his friends, by the very parents who disowned him upon his mutation.

He hadn't meant to anger Raphael by talking about their arrangements at the farmhouse; it had seemed like the best thing to do to sort out their current state. He hadn't known Raphael would be so sore about them staying here.

But hindsight is 20/20, and considering Raphael had just lost a brother, possibly two, it became clear that perhaps he should have been more considerate about referencing their inability to do anything about it.

It wasn't like the loss hadn't affected him, too. Leonardo had seemed like a very good and caring person, and Michelangelo had pulled him out of the underground mutant gang he'd been a part of, even after he'd betrayed the said poor turtle. Michelangelo had been a true friend. Mondo just processed complex emotions slower. Today he was fine, if not a little dazed, but he knew sometime later that week, he'd be off somewhere alone, either not feeling much of anything at all or practically drowning in a puddle of his own tears.

"Sensei, can you pass me the thermometer?" Donatello asked, snapping him out of his thoughts.

Splinter did so, picking the said instrument out from all the various packaging scattered on the table and handing it to his genius son.

Donatello lowered the thermometer into the water and pressed it to the tank's glass.

When it stuck, he examined all the tank's equipment, making sure everything was plugged in, turned on, and running smoothly. "Alright. That'll do it."

The air of the room changed so much in that moment they all may as well have breathed a collective sigh of relief.

Mondo turned towards the door again, and again saw no one there.

When he turned back, April was looking at him and following his gaze. She tilted her head back with a silent "oooooh" on her lips.

"We came back once we got all of Leo's essentials," she said. "We left without getting anything else. I'm gonna run to the corner store to pick up some stuff for lunch. I'm sure any stuff we have here is… less than fresh." Her nose crinkled at the thought. "Do you wanna come with?"

"Me?" Mondo asked.

"Yeah."

"Won't they mind that I'm…" he gestured to himself.

April waved a hand. "Nah. The guys have met Bernie before. It should be fine."

"Well, if you say so, I'm in."

Casey threw an arm around April's shoulder and jabbed a thumb at himself. "Count Casey Jones in, too, Red!"

Donnie glanced at them from where he sat beside Leo's tank with a kicked-puppy frown.

"You can come too, you know, Donnie?" April said.

Donatello shook his head. "I just plugged Leo's heater in. I have to monitor the temperature until it gets high enough and levels out, just to make sure."

"Well then you'll have to come another time," April said.

Donnie propped his elbows on the table. "I'm gonna hold you to that."

April waved at him and turned to go.

She, Mondo, and Casey went outside and to the Party Wagon.

Casey clicked his tongue, stopping outside the driver's side door and running a finger along the broken window. "Aw, nuts. That missile really did a number on the window."

"Careful," April said, getting into the passenger side. "Don't cut yourself."

"Casey Jones ain't afraid of a little glass- ow!"

April sighed and shook her head.

Casey got into the driver's seat and inspected his finger, which now had a very small cut on it, before buckling up and starting the engine. "How's your hand doing, Red?"

April looked at the blister on her wrist. "It's doing better than it was. Dad had me run it under some cold water as soon as we got here."

Casey glanced back to make sure Mondo was there, then pulled onto the long driveway.

The stones crackled under the tires and the van lurched side to side, then Casey turned onto the street and the path smoothed out.

Mondo looked out the window.

"Still looking for Raph?" April asked.

Mondo glanced at her for a second before returning to his window. "Yeah." He did a double take. "Wait. Who told you…?"

"Hey, don't take it personally," April said. "Raph's a little worked up now, and he's bound to take it out wherever he can."

Mondo gripped his armrests. "So this is what the whole trip's about."

April faced the windshield, but he could still tell from the bob of her ponytail that she was nodding. "Mostly." She turned to face him. "But it is partially about lunch, too. Unless you want a PB&J with year-old bread."

Mondo grinned. "I bet Mikey would eat it." He stiffened a moment later, realizing what he'd just said.

April didn't seem mad, though. She just smiled, a little melancholy. "Yeah, he would."

Mondo shifted in his seat and ducked his head. "I'm sorry. It's because of my stupid mouth like that that Raphael left."

"Don't beat yourself up," Casey said. "It's how Raph deals with things. He would have left for a while sooner or later, and it's probably good he did it sooner. He always comes back. Take it from someone he's stormed out on like, eighty times." He glanced in the rearview mirror. "And I've said dumber things. You were just trying to move on and make the most of the situation. Raph… tends not to move on."

Mondo hummed. He let quiet drift over the three of them as he tried to let their words comfort him.

The road rumbled under the tires. Wind from the broken window blew fresh countryside air over his face. He licked his eyes to keep them from drying.

"Are there gonna be any more customers at this store?" Mondo asked. "You said the owner's good, but…"

"Doubtful," April said. "He intentionally bought a store in the middle of nowhere because he thought no one would come.

Mondo Gecko tilted his head. "Why would he buy a store where he thought no one would come?"

"Oh, Mikey hasn't told you this story?"

Mondo shook his head.

April shifted to face him. "So basically, he trapped a whole bunch of beavers in the dream dimension using a book so that they couldn't escape into reality using other people's dreams as a portal, but it would only work if no one was sleeping nearby, so he decided to isolate himself to keep the beavers in the dream dimension."

If Mondo Gecko had eyebrows, they would have been so tightly furrowed right now they looked like one big, fuzzy caterpillar. "Are you pulling my leg?"

April laughed. "Unfortunately, no."

"So how do you tell if you're under the dream beavers' control?" Mondo asked.

"The guys mentioned seeing dreamlike qualities in their realities when they were asleep, like things that just didn't add up or seemed supernatural." She waved a hand. "You shouldn't have to worry about them coming back."

"I don't know, Sweetheart," Mondo Gecko said, "Things have a pretty dreamlike quality so long as you're around." He clicked his tongue, and would have winked if he had eyelids.

Casey shot him a look through the rearview mirror.

April giggled, but it wasn't a butterflies-in-the-stomach thing, more like she'd just been complimented by a puppy.

Which was fine, Mondo Gecko thought. Even if she didn't see him as a potential romantic interest, she was still nice to him, despite the fact he was a mutant.

Which was more than he could say for his parents.

The Party Wagon pulled up to the little convenience store and the engine promptly stopped, and the three got out.

Casey held the door open for April, the door ringing a bell as it opened, then went inside himself.

Mondo caught the door as it was closing and slipped inside.

The cool air hit him with a wave of memories.

It had been so long since he'd been in a store. He had forgotten what it felt like.

He'd forgotten the air-conditioned feel and smell about the place, kept cool to help preserve the items on the open refrigerated shelf's display. He'd forgotten how everything was illuminated in bright white lights so the customer could clearly see every product, how the tiled floors switched direction with every tile and made patterns on the floor with which way they turned. He'd forgotten the smell of fast food wafting through the air, whether it be soft pretzels or hot dogs on the little rotating grill they were displayed on. He'd forgotten the humming of the coffee and slushy machines, the sound of old pop songs playing on the overhead radio.

Mondo walked the aises slowly, taking it all in.

He'd shrunk a few inches when he was mutated, and now, walking through the store at the same eye level he'd been as a child, it brought back so many memories.

He found the candy aisle and remembered dragging his mom over to one in one of the corner stores in New York City, begging her to buy him whichever brightly wrapped candy caught his eye that shopping trip.

Sometimes, she amused him.

He remembered grabbing a newspaper from the front once when he was with his dad, and trying to read it like the grown-ups did, only to be tripped up when he came across their big words and complex phrases.

His dad had laughed and asked the cashier if they had any newspapers with kiddie pages, then had taken him back to the apartment and taught him how to play sudoku.

Mondo walked slowly through the aisles, taking it all in.

There was the junk food brand his dad always had in the cabinet, but he had never developed a taste for. He could still remember its taste, though, from one time his dad had shared that particular flavor with him. The taste would forever be burned into his tongue. It had only taken one time, yet he could remember it so clearly.

He didn't want to remember, for reasons more than its foul flavor.

Seeing batteries near the front desk, he remembered his mom taking him into a store once while his dad was at work, and asking for specific batteries for their radio so they could listen to music.

Jason approached the counter. He remembered being so bored the last time he'd been in a checkout lane, his father having taken him along to fetch some ingredients for dinner. Approaching the counter now stirred up these feelings from memory, as if he were supposed to still be programmed to sense them like here were any regular human being, but there was something new there, too.

April and Casey walked behind him, having finished their brief search through the small store's contents.

When the guy behind the counter approached the cash register, Mondo found himself backing up between his human companions.

"Hey!" Bernie said to April and Casey. "Long time no see!" His eyes drifted to Mondo.

Mondo shrunk as much as he could.

When he'd met April and Casey, he'd had the benefit of knowing they were already accustomed to interacting with mutants.

Every other human he'd come across, he hadn't had that reassurance, and often to disastrous results, right back up to the first time he'd come home as a mutant－or tried to, at least.

When Bernie's eyebrows shot up, he wished he could disappear into thin air.

"Oh," Bernie said simply. He reached over the counter.

Mondo stepped back, glaring at his hand like it was a deadly poison.

"I don't believe I met you before. Name's Bernie."

Mondo traced Bernie's arm back up to his face and, seeing no ill intent in his expression, slowly reached for his hand and gave it a quick shake.

When Bernie pulled back and started scanning the groceries, there wasn't a hint of distress about him.

Contrarily, Mondo stared at his own hand as if it would burst into flames.

"What brings you all out here?" Bernie asked, scanning a loaf of bread. "Vacation?"

"Uh… not quite," April said. "It's… a long story."

"Unbelievable story?"

"Yeah."

Bernie hummed. "I wouldn't put it past you all, considering what you got into last time you were here." He stopped scanning items for a moment, holding a box of crackers and smiling sheepishly. "Of course, that was mostly my fault."

Casey waved nonchalantly. "We deal with crazier on a weekly basis. You know, aliens, robots, ninjas, metal stuff like that."

Bernie arched a brow but didn't say anything. He scanned a block of cheese and slid it into the bag he was packing for them. "Alright. You're all set!"

"Thank you," April said, taking the bag.

Casey paid for their groceries, then the trio started to leave.

"Come again soon!"

As the humans loaded the groceries, Mondo stared back in through the store window.

"Wow," he said, "That was wild."

Casey slammed the Party Wagon's rear door. "If you think a convenience store is wild, then you need more excitement in your life."

"No, it's just… I met the shopkeeper, and…" And what? The store owner didn't try to attack him? He didn't try to kill him upon sight? He didn't scream and cry and call Mondo an abomination?

Casey got into the driver's seat, April, the passenger's. Mondo opened the side door and clambered in.

Mondo put his seat belt on and shrugged. "I met him normally." He sat back as the Party Wagon started. "I didn't think I would ever be able to do that again."

Leo's tank had evened out at a good temperature a little while ago, so Donnie asked Splinter to keep watch over him while worked on his current project.

Donatello walked towards the barn, where he knew his makeshift lab would still be waiting for him.

When he entered, he caught the familiar smell of sweet hay. The barn was still dusty, visible specs floating through the air where the sunlight caught them from the window or door.

Off to the side, Donnie saw Rockwell sitting on a hay bale, working on a laptop.

Donatello approached him, then stopped a considerable distance away as to not crowd him. "What are you working on?"

"I'm looking through the chemicals I compiled a list of when I was searching for the weapons' location. The fog's components may lead us to a way to protect ourselves from it."

"I can help you," Donnie said, moving to see the computer screen.

Rockwell held his hands up. "No!"

Donnie stopped and raised an eyebrow.

"I mean, you should be focusing on what your brother needs. Leo, that is."

"I've already checked on him. He has everything he needs."

"Well, I still do not require an assistant."

Donatello stiffened. "Oh." He rocked on his feet. "Well I guess I'll get to my own experiments, then."

"Yes," Rockwell said, "Please do."

Donatello shot Rockwell a wounded expression, then crossed the barn to where his desk had been last invasion.

Last invasion. Donatello didn't like how he thought of the event, as casually as if he were saying, "last tuesday".

Yet, here it was, a recurring thing, and it seemed to get scarier every time.

Donnie spotted the corked vials on his desk－Spinter must have put them there for him－ and went about pouring them into the various different beakers and trays he'd had them in before the invasion.

The most recent invasion, that was.

He poured one test tube into another, creating an orange color that resembled all too much the substance that had put Leo in the state he was in now.

The substance Donnie had created.

Donatello focused on his chemistry. He tried to drown the other thoughts out in numbers and calculations, but his busy mind found a way of bringing them back up.

Especially now, surrounded by the same setting he'd been in for three whole months waiting for Leo to wake up, Donnie couldn't shake the thoughts bubbling to the surface.

For three months he had worked, desperately trying to make a medicine for his unconscious brother. His brother with whom his last interaction was an argument. For three whole months, he wondered if his brother would die with his last impression of Donatello being the genius turtle doubting him.

And for what, so they could use the turtle mech?

Donatello had had faith in his machine, that it would allow them to save the city from the Kraang invasion. But Donnie spent the next three months wondering if his insistence to use the mech had, deep down, been out of some ulterior motive－pride, perhaps. Self-absorbance. Maybe it had been a chance to show off his skill to the world.

Leonardo hadn't had the same faith in Donnie's creation as Donatello had. And Leo was right.

Donnie caused them to be separated in the middle of the Kraang invasion because of an argument. Leo would then walk into the Shredder's trap, all alone. Because of Donnie.

And even after they were separated, Donnie still insisted on taking the mech. The remainder of the team trusted him and tried to fight the Kraang in the mech.

Leo was right. The mech didn't work.

And like Mikey and Slash now, they'd been forced to leave Splinter in the city.

Leonardo had always been cautious of Donnie's inventions. He'd doubted Metalhead, even to the point of suggesting Donatello's own creation could be working as a Kraang soldier.

Which wasn't an unfair point, considering a Kraang had once hijacked Metalhead's controls.

Donatello measured out the amount he wanted, and poured the beaker into his main solution. He picked up the solution and gently swirled it, blending the chemicals together with the motion of his wrist.

The only person who never seemed to doubt Donatello's intellectual pursuits was Mikey.

But then again, Donnie thought, Mikey would believe in anyone and anything. What did his support mean?

Donatello held his head in his hands, cursing himself for thinking such about his missing brother.

But Mikey had been wrong. Wrong to have faith in him. Donnie failed.

Leo had been right to doubt him.

Leo had been right to question his inventions. Twice now, Leo was a victim of Donnie having too much confidence in his work, or in even making the blasted things in the first place. If not for Donnie's retromutagen, Leo wouldn't be where he was now, trapped in that stupid cage like some helpless housepet.

No wonder Rockwell didn't want to work with him. No doubt the psychic could see right past his intellect into the sorry excuse of a person that lay under it.

As if to prove his point, Rockwell stood and left the barn.

At least someone still had common sense like Leo's not to be around Donnie and his dangerous projects, the purple-clad turtle thought.

And yet, there he was, still working on his chemistry project, once again trying to clean up the mess he'd made.

Hopefully he could do so without messing anyone else's lives up.

He looked at the vials and beakers he held like they were filled and covered with blood. They might as well have been. Here he was, thinking he could fix the problem with the exact same thing he'd screwed everything up with.

As if his concoctions hadn't hurt Leo enough already.

All because of what Donnie thought he could do.

If only Leo were there to tell him otherwise.

"Leo…" Donnie buried his face in his hands. "You always doubted me. Why…?" He buried his face in his hands. "Why did I never stop to realize you were right?"

Raphael walked into the clearing where the farmhouse stood. He stepped off the path he'd been following through the forest and approached the house.

He suspected anyone looking out the windows would be able to see him now that he was out of the forest, so he hurriedly wiped his cheeks dry. He hoped everyone would be wary enough of him from his outburst not to get close enough to see his reddened eyes. If anyone asked, he could say it was because of a lack of sleep.

Raphael had spent enough time in the forest that his pulse had returned to normal, his vision had cleared, and he no longer heard his heart pounding inside his head. He still noticed a lump in his throat and knot in his chest, but he could deal with being around other people with those sensations. He'd done that plenty.

Raph reached for the doorknob, only to hear his heart echoing in his head again. His hand clenched by his side.

Splinter would be in there.

Raph turned and elected instead to go to the barn.

The barn door hung ajar, so Raph grabbed it and peeked around it into the room.

The barn looked just about the same as Raphael remembered it, Donnie's makeshift lab set up on a table in the back under the hayloft. The genius turtle sat there and worked away at his station.

Raphael glanced at the forest path he'd just come from. Maybe it wouldn't hurt to go back and stay away a little while longer.

He gazed back at his purple-clad brother and decided against it.

He was smart enough to know Donatello hadn't slept the night Leo got unmutated, and he wouldn't have been able to on the way to the farmhouse, which meant Donatello had gone over sixty hours without sleeping, the time being long past midday at the moment.

And judging from Donnie's focused work right now, he wasn't planning on quitting anytime soon.

When Raphael had yelled at them for not doing more to help Mikey and Slash, he hadn't meant Donnie. Donnie always did whatever he could to help anyone who needed it, even at the cost of his own well-being. If Donatello had abandoned their fellow turtles at the city, it had been because he truly didn't see a way around it.

Raph could only hope he hadn't caused Donatello to sacrifice more of his well-being than the purple-clad turtle already would.

Donatello needed rest.

Raphael would tell him such. He walked towards Donnie's desk.

Donatello would not respond kindly to being told what to do after the two had just been in an argument, so Raphael mentally fished for a conversation starter to bring the air back towards normal before he tried to tell the genius to get some rest. The entire thing sounded uncomfortable to Raph, but while there were problems to be solved, Donnie wouldn't get any sleep unless he was told.

Not that Raph had been sleeping a decent amount, either.

His eyes landed on the chemicals his brother worked with, and Raph remembered Donnie had never really explained what he was working on, so much as deflect from the conversation. That could be something to talk about.

Donatello looked up when he heard Raphael approach. He put the vials down. "Raph."

"Hey." Raph stopped beside Donnie's desk and rubbed the back of his neck. "So, uh…"

"I'm sorry."

Raph started. "Huh?"

Donnie picked a pencil off his desk and twirled it in his fingers. "I shouldn't have been so quick to lash out at you. We're all really stressed about what happened yesterday, and I just made things worse by yelling."

Raph processed his apology, then gave an awkward nod and let his hand fall from his neck. So far so good.

If he could keep things from getting tense again.

Silence formed and grew as the two stared at each other.

Raph remembered his backup plan and indicated the chemicals. "What are you working on?"

Donnie jumped. "Uhh, same thing as last time." He grabbed a test tube, as if to hide the contents in his hand even though Raph had seen it the second before, and continued working. "Just some basic chemistry stuff." He poured the tube into the main beaker and watched as the chemical reaction changed the solution's color."

Raph furrowed his brow. "Yeah, but what exactly are you－" He trailed off, noticing the solution's new color. "Huh. That looks about the same color as retromutagen."

He would have left it there, had Donnie's eyes not grown wide, and had he not repeatedly glanced from the concoction to Raphael.

Raph looked at the beaker. "It is retromutagen?"

Something about the liquid in that beaker made his heart start pounding in his ears again. He wanted to punch the retromutagen－ a horrible idea, by all accounts, but that was what some part of his brain was telling him to do.

Raph's brow creased. "Why didn't you just tell me that the first time? And that are you gonna do with it, anyway?"

Donnie held his palms up, looking at the retromutagen-in-progress, then at Raph. He sighed and averted his eyes. "It's… It's for Leo."

Raph raised a brow. "Uhhhhh, genius, that stuff's done all it can do to him. It's not gonna work on a regular turtle."

Donnie closed his eyes and pinched the bridge of his nose. "I mean… I mean it's for Splinter."

Raph clenched his fists. "You know, if you're gonna lie to me, at least give me enough credit to make up a story that makes sense the first time!"

Donatello waved his arms over each other in a wait a minute gesture. "I am telling the truth! I wanted to give the retromutagen to Splinter so that…!" He dragged his hand down his face, letting out a long, tired sigh. "The main reason someone wouldn't mutate with Splinter's DNA the same as they would have fifteen years ago is because, obviously, he's a rat now. So I thought, in theory－"

"If you unmutated Splinter and mutated Leo with his human DNA," Raph said, catching on, "He'll go back to how he was!" Raphael grinned. "Donnie! That's amazing!"

Donatello didn't meet his praise with the enthusiasm Raph expected, instead averting his eyes again with a frown tugging on his lips.

"Donnie?" Raph's grin slipped. "What's－"

"The reason I didn't tell you."

Just like that, Raph fell from the high skies of expectation into a deep pit of dread. If this day planned to take him on any more of a rollercoaster, he might just lie down on the ground and curl up into a ball.

"In theory, this plan should work," Donnie began, "But there's also a million reasons it shouldn't, starting with we don't know if it was Splinter's DNA we were mutated with. We could have been mutated with the last people who took us out of the pet store cage, or with the employees there. The only way Leo would have had Splinter's DNA to begin with, would be if Splinter had been the last person to touch him before the mutagen struck, which we can't be sure of, especially considering turtles generally aren't petting animals.

"Also, we don't know how mutagen really works. I can't say if the mutagen would pick the same alleles of the DNA to mutate Leo with if we were to redo his mutation. The selection could be liable to repeat the same pattern, or it could be random.

"Even if he does end up the same physically, his brain would have shrunk and grown again, which is an unprecedented transformation. Theoretically speaking, there's not enough room in his brain right now to compensate for all the functions his previous brain was in charge of. If that information is lost with his second transformation…" He trailed off. "There's no studies on how that might work, or… what memories he might retain. Or rather, might not retain."

Raph let out a short breath through his dropped jaw.

"I didn't want to tell you because…" Donatello held his hands out in front of him, like he was trying to gesture along with what he was saying, but body language didn't carry the weight of the words he wanted to convey. He shook his head. "Leo's chances of going back to normal are… infinitesimal."

"So… if this doesn't work?"

Donnie shrugged. "It's my only plan." He tapped his desk. "If this doesn't work, then there's nothing I can do for him." He met Raph's gaze. "And statistically speaking, even from the very little data I have? Don't get your hopes up."

Donatello may as well have crushed him into bits right then and there. Coming from another scientist, it wouldn't have hurt so bad; he could have just asked Donnie to take a look at it. Donnie always figured something out.

But this, telling him his big brother was almost certainly gone, was the Donnie who always figured something out. The Donnie who always kept looking for a solution no matter how long it took. The Donnie who stayed up until the odd hours of the morning because he'd made a promise he couldn't keep and was determined to see it through.

That Donnie was telling him that Leo was good as gone.

Raph tried to swallow with a dry mouth. That lump in his throat was still hanging around. "How long until the retromutagen is finished?"

Donatello glanced around his worktable. "Fortunately, I'd already been several months into making this batch by the time the last one got… used up. It should be done in a week or two, maybe even a few days, but I wouldn't count on it. Something always goes wrong and I have to make up for lost time." His eyes hovered on the beaker of incomplete retromutagen. "But until then? I'd appreciate it if you didn't tell anyone." He placed his hand on the beaker. "There's no sense in giving anyone false hope."

Raph nodded.

He and Donnie stared at the worktable, each lost in their own thoughts.

"Well," Donatello said, sitting down, "I may as well be working."

Raph nodded, then turned to leave. Donnie needed all his focus to stay on track, tired as he must be by now.

Raphael stopped and turned to address his brother. "Oh, and Donnie?"

"Hmm?"

"Get some rest."

Donatello waved a hand. "Yeah, yeah. Soon as I'm done with this part of it."

Raphael nodded and left him to make his cure for Leo.

Or what would hopefully be the cure.

Raph didn't want to think about what would happen if it wasn't.