The Lucky Cat Café had been locked up when they left, leaving Tadashi to search his pockets frantically until he accidentally dropped the spare key and ended up kicking the door in frustration.

Eventually, he got down on his hands and knees, shivering from the rain that drenched him, and searched the bushes. He was shaking so hard by the time he found it that he nearly dropped it again when he went to shove it in the keyhole.

Finally, the door opened. and he rushed into the house yelling, "Hiro! Where are you?"

Usually, when Hiro was upset, he hid in his room, so that was the first place he went to check. Turned out he wasn't even that far away. The crouched form sitting at the top of the stairs, waiting for him, was his little brother.

Exhausted and panting, Tadashi climbed up the stairs, his hat still pressed against his chest, and collapsed next to Hiro.

Seconds passed that turned into minutes. Neither really wanted to speak because that would mean the dream they'd shared of a happy future where both of them were alive and together was really ending.

Deep in his own thoughts, Tadashi thought of someone who had pushed him out of the way. He'd wondered who it was, just never very hard or intently.

And now he knew why.

Because he'd always known who had pushed him out of the way. It was the same reason why he'd never asked the doctors about Hiro or taken him to the hospital when he realized he couldn't speak. It was the reason he never really talked to Aunt Cass. He was afraid someone would tell him what he knew now.

Sitting beside him, Hiro looked miserable. A coat of ash turned his black hair almost white, his clothes were reduced to burned scraps hanging off his frame. Worst of all, half the skin on his face was blackened around edges, peeling away to reveal the raw muscle beneath.

Hiro had tried to tell him.

He hadn't listened.

"Did you die because of me?" Tadashi finally asked. "If I had never gone in to save Professor Callaghan, you'd still be alive." He smiled bitterly, self-loathing etched into every feature of his face. "I really let you down, Hiro."

Cold air brushed his palm. He looked down to see Hiro's hand on it.

My choice.

Hiro signed, his body language exuding a confidence he rarely showed.

I chose to follow you. I chose to save you. No regrets. He paused and softened. No apologies, Dashi… Someone had to help, right?

"Not you." Regret gathered in Tadashi's throat, choking him. "It wasn't- I wasn't… I wasn't supposed to lose you. This was supposed to happen. I-" He wasn't breathing right. Air flowed into his lungs in short gasps and pain built in his chest as his muscles tightened from the lack of oxygen. It was making him feel dizzy. Spots danced around the edges of his vision as he tried desperately to make his breathing to regulate itself.

Then a head of spiky black hair leaned against him, cooling his skin.

And his breathing steadied, calm with his brother so close, so real.

A single thought occurred to him that chased that brief calm away with the speed an brutal efficiency of the sun chasing away the morning fog.

Wasn't this the part where he was supposed to let Hiro go? Let him smile and dissolve into light so he could see their parents again and be at a peace and Tadashi could…move on? How? How was he supposed to live in a world that didn't have his little brother in it?

Tadashi latched on to Hiro, his arms wrapped around his slender body, and cried, "I don't want to lose you, too, Hiro. I can't! I can't I-"

Ghostly fingers pulled his hands away, guiding them into shapes and words Tadashi could just barely dredge up from memory.

Don't be dumb, Dashi. I'm always going to be with you.

For a while, they just held each other. It didn't seem fair that the world that took their parents from them had decided it could take more. It didn't seem fair that Hiro's life had to end when it was really just beginning, when his big brain could do so much for the world. None of it was right or fair. But it also wasn't something they could change.

Tadashi screwed his eyes shut; keeping them shut as long as he could because he could guess what he would see when he opened them. He knew he didn't want Hiro to leave. He also knew he couldn't make him stay, and when his arms closed on empty air and the cold touch on his skin faded to a dull echo, he pitched forward, gasping and trembling, his hands laid flat against the wall.

He bowed his head, willing to the world to stop moving. Willing time to stop.

It'd been two weeks since Hiro had left for good. Two weeks and Tadashi had almost never left his room. Sometimes he helped Aunt Cass prepare for the eventual reopening of the Lucky Cat Café, but he rarely spoke to her and would usually return to his room once the work was done. There, he would do maintenance on Hiro's robots, cleaning them and keeping them functional. Even his battle bots got the same tender treatment as the rest.

Sometimes, he would stare at status of the offline tracker. There was a small, fluttering hope in his chest that hoped it would come to life someday. And lead him to his living brother, For the most part, however, he just stared at the broken tracker to punish himself, playing the events at the fire over and over in his mind, trying to find what he could have done or said differently to save his brother. He replayed the memory until it mutated into a nightmare and he could hear the sound of his brother's dying screams whenever he closed his eyes.

Baymax stayed propped up against the wall, nothing but a constant fixture in the monotone world his life had become until the day he stubbed his toe on Hiro's bed.

"Ow!"

It was too late to stop Baymax's activation by the time he'd realized what he'd said, so he just walked over to his personal healthcare assistant and waited.

"Hello, my name is Baymax. I heard you were in distress. From 1 to 10, what is your level of pain?"

Frustrated, Tadashi fell into the seat by the computer and raked a hand through his hair, blowing air out in a long exhale while his robot observed him. "I'm not really in physical pain, Baymax."

"My scanners do not detect any physical injury." Of course not. Baymax hadn't been programmed to recognize emotional pain.

As though in answer to his thoughts, Tadashi watched in awe as his robot downloaded an entire database on emotional pain. Seriously, maybe he'd gone a little overboard on Baymax. Then again, it felt good to feel pride in something he'd done, he'd created. It was a nice reminder that not everything he touched burst into… that not everything he touched got messed up.

Baymax turned to him and said, "I believe you are suffering from the depression. My database recommends care and the support of your friends and relatives."

Big, white inflatable arms pulled Tadashi into an awkward hug. "There, there. It will be okay."

Tadashi pushed him away. "Baymax, I don't need this. Really." A circle of pictures featuring Gogo and the others glowed above Baymax's hand.

"I am calling your friends now."

Panicked, Tadashi shouted, "Cancel that call. It- it would be detrimental to my mental health!"

To his surprise, Baymax listened. "Would it really?"

"Yes. Now, please, just leave me alone."

He turned his back on the robot, fully intent on ignoring it. Then he heard a name he couldn't ignore.

"Hiro."

"What?" Tadashi demanded, his voice strained close to breaking.

"Hiro."

Following Baymax's gaze, he saw the empty bed, his hat sitting, untouched, on top of it.

He swallowed hard. "Hiro's not around, Baymax."

"When will he return? He is my patient. He is in my care."

"I know, buddy. But Hiro di-" Stop it. Stop acting like it didn't happen. Stop acting like he's coming back. "Hiro is… Hiro's gone. He can't be your paitent anymore."

"I don't understand. Your brother was in excellent health. He should have lived for many more years."

"Believe me, I know. I know he should have. Better than anyone." After all, Tadashi was the reason he didn't. Suddenly feeling too exhausted to speak, he stood up, walked into his bedroom, and shut the door, leaving Baymax to ponder what he meant.

His robotic gaze still focused on where Tadashi's retreating back had been, Baymax looked pointedly at his chest and said,

"Hiro is not gone. Hiro is here."

AN: And that's the end, folks. Thank you for taking the time to read this and I hope you enjoyed it. If you've read Twist of Fate by WilliamBlueJay17, then you pretty much know what happens next. And if you haven't, then I highly recommend that you do. As far as I know, that's the go-to story for finding out how Tadashi would have handled being the main protagonist of Big Hero 6.