Author's Note: Hello! This is a post-movie AU that will pull elements from the Big Hero 6 comics and manga. It also pulls in a theory that has recently become popular and that I completely agree with (obviously I won't give it away yet). The first chapter is mostly an introduction to the characters, but more action is coming. I hope you enjoy!

One of the greatest superhero groups of all time sat in a circle in the center of the room, about to look through carefully documented notes. Around them were displays of super suits, comics, and figurines. Here, they came to hear a case, share opinions, and come up with a suspect.

And fifteen year-old Hiro Hamada was busy comparing his height to the other team members'.

Hiro had been waiting for his expected growth spurt for the last half of his life; and during the last year, it finally started. Since then, he found himself constantly comparing what he feared might be his permanent height to the world around him. He was still shorter than Aunt Cass (NOT acceptable) but was now perhaps taller than Gogo. If only there were an easy, no conspicuous way to compare heights…

" – And I figured this boy might go to his neighborhood playground. So I went and I talked to him and I asked him about the attack from the demon cat. And he was like, 'Nah man, it was a robotic cat.' And of course I freaked out 'cause ROBOTIC DEMON CAT! And –"

"Wait, demon cat?" Hiro interrupted his friend, Fred, who had been excitedly pacing around the room while ranting before being interrupted.

Gogo, the girl that Hiro was definitely taller than, rolled her eyes. "Kid got left home alone and attacked by a demon ROBOTIC cat. He wasn't physically harmed, and since he suffered from hallucinations, the cops didn't believe him until they saw the security footage of a freaky cat coming in the door."

"Oh," Hiro said, embarrassed that he had probably zoned out for a long time to have missed all of that. Better start contributing now. "So someone has a problem with the kid and wanted to give him a scare."

"Or the parents," Wasabi added, always noticing when a potential argument was left out. "They could have a problem with the kid's parents."

"True," Fred nodded, still pacing.

"But since we know that the kid lives with his dad," Gogo paused to give Hiro a pointed look that said that he would have known that fact if he paid attention. "Then what if his mom wanted to get revenge on his dad?"

"Maybe," said Honey Lemon, the tallest person in the entire group. "But you said that he had a deathly fear of cats. Whoever bothered to make a robot just to scare a kid had to have known that. Does he see his mom often enough to share things like that with her?"

Gogo shrugged. "No idea."

Hiro thought about it. He had used his inventions to occasionally scare the crap out of people (his guardian, Aunt Cass, could tell stories about Hiro using megabot to scare his brother right as he was getting into the shower), but he couldn't see why someone would want to traumatize a boy who already had an unstable mind. He doubted a mother would stoop that low. He also doubted that a kid would make an enemy that diabolically evil. So it was more likely that this kid was one of many victims. But the criminal still knew the kid well enough to discover what he feared.

"Guys," Hiro spoke up, causing everyone to start at the sudden sound. "Who would know a child's fears?"

"Their friends?" Wasabi began. "Their diaries? Their teachers?"

"Yes," said Hiro. "People they trust. Now, who would a boy with hallucinations trust?"

Gogo gave him a funny look, understanding Hiro's thought process. "You think he has a psychiatrist with a double life."

Hiro nodded. "It makes sense."

"There's not a lot o' evidence to it," Fred said, tapping his chin and looking like a TV detective. "But we can check for it. Villains with daytime jobs rarely have only one victim, so it shouldn't be hard to find dirt on him or her if there is dirt."

Honey nodded. "We can see if there have been any other attacks and then cross reference any victims with the psychiatrist's patients."

"Okay!" Fred exclaimed. "Planning time. We find out who the kid's psychiatrist is. I'll ask the kid if he knows of any other kids that've gotten scared. I guess I'll also find out who the psychiatrist is when I ask the kid. Wait, I think I'm doing all of the work."

Honey giggled. "It's okay. We helped plan."

"And I have a paper due tomorrow, so it's not like I have nothing to do." Wasabi added, standing up.

"Just call us as soon as you learn anything," Gogo said, also standing up. Hiro immediately followed, still wanting a chance to hopefully confirm he superior height.

"Alright, see you later!" Fred called, waving as they left.

…

Hiro opened the door to the Lucky Cat Café, hearing the bell chime as he stepped in. It was eleven, so all of the chairs were empty. Hiro went to the back of the shop, clambered up the steps, and arrived in the kitchen. The overhead light was on, and there was a note and a plate on the table.

Picking up the note, Hiro read:

"Sorry I couldn't wait up. I'm about passed out on allergy medicine, and it's only ten. I'm probably asleep by now, but I saved you some leftover cookies. Enjoy! You better be fast asleep by eleven-thirty at the very latest.

Love,

Aunt Cass"

Smiling, Hiro shoved one cookie in his mouth and took another for the road. He climbed more steps until he reached his room.

He tossed his backpack in the general direction of the floor near his bed and sat down on his chair. Still chewing, he flipped on a lamp and stared around his room. Sometimes, as a child prodigy and an awkward pubescent teenager, he had trouble focusing on one thing as well as his college-aged friends did. Tonight had been an example of that. Hiro sighed; he hadn't seen this problem coming when he founded the team.

Looking over at the other side of the room, Hiro was reminded again of why he founded the team in the first place. Half of the room was hidden by a room divider. On the other side, Hiro knew there was Tadashi's bed, Tadashi's hat, Tadashi's dresser, Tadashi's books, Tadashi's action figures. Most of everything that Hiro's brother once possessed, read, worn, or played with was behind the screen. Hiro kept the screen closed most of the time, occasionally going in to get something when he needed to remember his brother. His brother was the reason that Hiro and his friends started Big Hero Six. Tadashi Hamada wanted to help people. He wanted to heal people. He was the annoying person that would say that he wanted world peace when you asked him what he wanted for his birthday.

God, Hiro missed him.

He could only imagine how he would react to Hiro turning himself, the robotic nurse, and all of their friends into superheroes. Hiro smiled as he remembered Tadashi's face when he discovered that someone invented the water-proof book. He imagined Tadashi's reaction would look something like that.

Hiro continued to stare at the divider. Aunt Cass talked about maybe putting some of the stuff in storage, or maybe moving some of the stuff around to make it a little less obvious that two people once shared this room. Hiro knew she was right, but he kept putting it off. Tadashi not being alive still seemed unreal. Getting rid of Tadashi's stuff felt like getting rid of Tadashi.

Sighing again, Hiro turned back to his side of the room, staring at the shelves of robots lining the wall. The important thing, Hiro reminded himself, is that I am using my big brain to help people. Just like he wanted.

Once he finally finished both cookies, Hiro yawed and stretched. Time for him to get out of this comfy chair and into his bed. He stood up and flopped down on his bed with a little bounce. He wrapped his arms around his pillow was preparing to fall asleep when he felt something under his arm. Confused, he moved his fist to grab it and look at it.

It was a small card, like a business card, except it was blank. Furrowing his brow, Hiro flipped it over to check the other side.

1:00 at the location of the fire.

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