Notes: This isn't part of the Big Heroes series. It's a different AU for how things could have happened with the movie and the result of reading too many "Callaghan kidnapped Tadashi" fics combining with my own headcanons. Honestly, the idea just struck me and the next thing I knew I had nearly three thousand words of what has to be one of the more disturbing things I've ever written.

Father Knows Best

Tadashi ran. It was, he admitted privately, probably not the smartest thing to do but his only other option seemed to be staying put and that was just stupid. It didn't help that he was honestly terrified. If he hadn't rescued Hiro from so many bot fights gone sour, he'd probably be too scared to think straight. As it was, he knew he could perform under pressure and even now was searching for a way out.

Tadashi knew he had to be in some sort of bunker, probably even underground, but it also looked professional and that meant there had to be some sort of emergency exit, likely complete with signs. So he kept his eyes peeled as he ran and there! He hit the door at a good clip, making it fly open under the force of his body and then he was out in the fresh night air. He gulped at it it greedily even as he paused to take stock of where he was. It wasn't a street or road like he'd hoped. In fact, based on the location of the city lights, he was on one of the islands in the bay. He cast frantically about. There had to be some docks or a helicopter pad or something. They'd gotten on the island, after all, so there had to be a way off.

A noise from behind made him look back to see what looked like dark shadows spilling out of the door into the night. With a panicked shout, he ran, not really heeding where he was going as long as it was away. Then the ground gave way under his feet or wasn't there to begin with and Tadashi yelped as he fell, hands and feet scrambling to catch himself on something that wasn't there. There were twisted, jagged spikes of metal below him and he was going to be impaled long before he hit the ground, he realized in terror. Then his fall was halted by something grabbing his feet and hanging him upside-down. A spike was mere inches from his eye. He let out a shuddering breath, but then had trouble breathing in as he felt the microbots crawling to cover his body even as he was pulled up and out of the hole in the ground. His limbs were firmly restrained once more by the time he was brought face-to-face with Professor Callaghan.

Tadashi had firmly lost control of his breathing, definitely hyperventilating and a step away from outright crying in distress and fear because he was trapped on a death-trap of an island with this man wearing the face of someone he'd once trusted. He didn't want to be here. He wanted this to be some sort of nightmare that would soon end and he'd wake safe and sound in his own bed, Hiro in the next bed over and the familiar sounds of Aunt Cass and Mochi coming up from the floor below. Instead, he'd been kidnapped and he didn't even know why.

"Shh. You're alright. You're safe. I won't let anything hurt you," Robert Callaghan murmured as he reached out and affectionately held Tadashi, ignoring the way Tadashi stiffened at his touch. It just made things worse, having Callaghan act all fatherly. Once, Tadashi had adored the man for willingly being the male role model and father-figure he hadn't had since his own father had died. Now it just reminded Tadashi of exactly how twisted this whole situation was. The worst part was it actually was helping him stop hyperventilating.

"Why are you doing this?" Tadashi gasped brokenly as Callaghan continued to hold him and rub his back.

"I knew you were going to be something special the moment I first met you, but I didn't know how special until I introduced you to Abigail. It was like watching sparks fly. You became so close and it was such a pleasure to witness it, seeing the steps as they happened and knowing where they'd eventually lead. Knowing that you'd end up together and even, one day, become my son," the professor said, pulling back to look at Tadashi as he spoke, but keeping his hands on Tadashi's shoulders in a friendly gesture even as he controlled the microbots still holding Tadashi bound and captive. Then his face darkened and his grip on Tadashi's shoulders grew painfully tight, making Tadashi gasp.

"Then Krei killed her, murdered her in front of a whole slew of witnesses, and got away with it! And I saw you drowning yourself in your work, even pulling all-nighters, working on that robot as if it would've made a difference, as if it could have stopped her death if it had just been made earlier. It about killed me, watching that."

Callaghan's grip had loosened and turned affectionate once more, rubbing Tadashi's shoulders and upper arms in what was no doubt supposed to be a comforting gesture.

"The moment I saw Hiro's microbots, I knew what I had to do. I didn't want anyone to get hurt, of course, but I had to hide my tracks. And I knew I couldn't wait any longer when I watched you leaving with your brother. I set the fire and was going to leave without a trace when you came in looking for me. I knew you would; we have such a close bond. It was a work of a moment to rescue you from the explosion, to get us both to safety. And it works out so brilliantly this way. They think we're dead, so no one's going to come looking for us."

"You can't keep me here forever," Tadashi protested once he found his voice again.

"Oh, we won't be here forever. Just long enough to set my plans into motion. Krei needs to pay, Tadashi, for what he did to Abigail and I'm going to make sure he does."

God, Professor Callaghan had gone off the deep end. He was sanely rationalizing his actions, even though they involved theft, arson, and kidnapping, not to mention planning to ruin a man's life. It made Tadashi tremble as the enormity of what the man had done, was still doing, hit him.

"Come on, let's get you inside. I don't want you catching a chill," Callaghan stated in response to Tadashi's shiver. As the microbots carefully carried him inside, Tadashi realized he had no clue how he was going to get out of this.

At some point, Robert Callaghan had apparently convinced himself that Tadashi was his son in all but blood, never mind that Tadashi and Abigail had emphatically not been dating nor even considering it. They'd just been friends. Good friends, sure, but nothing like that. Tadashi personally leaned towards asexual, and not the gray kind, while he was pretty certain Abby had had a thing for the fairer sex. He didn't dare try to explain that to the professor however. He was afraid of what the man would do to him if Tadashi burst his bubble that badly. As it was...

"We weren't dating, you know. Abigail and me. We weren't-"

"You would've been by now if not for Krei," Callaghan insisted.

"But-"

Callaghan silenced him by pressing a hand to Tadashi's mouth.

"Shh. Don't worry, son. Krei's going to pay for what he did and then everything will be alright. We'll start over, you and I." There was a fanatical look in his eyes that frightened Tadashi, which was why he complied when Callaghan ordered, "Look over the numbers again."

"Yes, sir."

As it was, Tadashi was currently his very unwilling accomplice. Callaghan had him working on the numbers for the portal, double-, triple-, and even quadruple-checking them to make sure it would work. Tadashi did it partially because it was really the only thing he was allowed to do and boredom was bad enough when you weren't in a kidnapping situation, but mostly because Professor Callaghan really scared him.

It wasn't just the way Professor Callaghan kept calling Tadashi "Son". It wasn't even that he insisted Tadashi refer to him as his father. It was his "Father knows best" routine. Any time Tadashi tried to escape, to resist, to just be anything other than obediently compliant, the man would grow angry or, worse, cold. Then he'd do things to Tadashi, saying, "It's for your own good." Things like locking him into a pitch black room for indefinite amounts of time, forcing him to wake up and go to bed at odd intervals, even once taking his belt to Tadashi's backside for even daring to suggest abandoning the plan against Krei. It was stressful and wearing Tadashi down.

Unfortunately, Tadashi suspected that was the point. At some point, the professor must have read a book on psychology because every so often he seemed to test Tadashi for the symptoms for Stockholm Syndrome. That, of course, just frightened Tadashi even more. He'd embeen/em emotionally attached to the professor. The idea of remaining so considering the circumstances...

Tadashi shivered, then jumped in his seat a moment later when a blanket was suddenly wrapped around his shoulders.

"Don't want you catching a cold, son," Callaghan said with an affectionate tousle of Tadashi's hair before he went back to what he was working on. Tadashi hunkered down in the blanket as he turned back to his numbers, the handcuffs binding his ankles to the seat clinking as he shifted. He wished he could go home.

Tadashi was fairly certain he was the only reason Robert Callaghan even bothered to stop to eat at all. The man was fanatical as he reverse-engineered Hiro's microbots and figured out how to make the portal work outside of the room it had been sealed in and only seemed interested in food at all because he was determined to keep Tadashi alive, whole, and healthy.

The man also insisted on 'family' meals. The table was small and intimate and the conversation was kept to lighter topics as they ate. If Tadashi didn't have his legs bound to a chair that was bolted to the floor, or wasn't stuck eating with just a spoon because the professor had decided the other utensils were too dangerous for him to have access to, it would've come across as nice. As it was, Tadashi was starting to struggle to find conversation topics that didn't bring up the weather he hadn't been exposed to in weeks, what they were currently working on, or Tadashi's real family. As it was, the conversations drifted towards Abigail and what the professor had thought was going on between them a little too much for Tadashi's comfort. Not only did it bring about a return of Callaghan's assumptions for what Tadashi's position in the professor's life should be, but it all too often ended with the man ranting and raving about how he was going to make Alistair Krei pay for what he'd done to 'their' beloved Abigail.

Tadashi had seen the videos - Callaghan had forced him to - and Tadashi wasn't certain Callaghan was even right. Sure, Krei had given the go ahead, but there were other scientists involved who hadn't argued. If the fluctuations were within the set parameters, then there would've been no reason to believe it would cause an issue. There was also the fact Abigail had been willing to go into something she'd no doubt known was potentially dangerous. She'd always been a bit of a daredevil and Tadashi had both wanted to introduce her to Gogo and put it off for the same reason: they'd have gotten on like a house on fire.

Still, Abigail wasn't suicidal and it had hurt watching the return portal go up in flames. He hated Professor Callaghan for making him watch his friend die. He clung to that emotion too, even if he had to bury it deep so his kidnapper couldn't see it. He hated the man for stealing his brother's tech, for deciding his pain was worth more than other people's, for ripping Tadashi away from his family. He hated the man for what he'd become even as he mourned the man he'd once been. And it gave him the determination to keep going, despite the random rules and "For your own goods" and the professor verbally tearing him down before making him recheck the numbers yet again. Tadashi was going to survive and he was going to get back to his family.

Something was going on. In the past few weeks, Tadashi had gotten used to the professor disappearing for a few hours every few days as he checked up on where-ever he was mass-producing the microbots and somehow gained supplies, mostly food. Tadashi suspected the man was stealing because dead men don't have debit cards. But the day the man had decided to shut down the mass-production and bring the microbots to the island so he could start moving the portal, he came back with the microbots and a scowl.

"What happened?" Tadashi ventured. When Robert Callaghan's scowl hit him full force, he quickly tacked on, "Father," and looked down, hoping to appear contrite. Something about the expression must have set the man off, however, because Tadashi found himself being hauled out of his chair by the microbots and thrown rather roughly into what he thought of as the Dark Room. Tadashi didn't know how long he spent in there - it was impossible to tell time in the pitch dark - but he had the distinct impression that he was being punished in lieu of someone else.

What had to be be hours later, a rather contrite-looking Callaghan let him out. He ran his hands over Tadashi, as if making sure he was uninjured, before pulling Tadashi into a hug.

"I'm sorry, Tadashi," he murmured into the younger man's ear.

"I'm sure you had a reason for locking me up," Tadashi carefully stated, making it sound like he was accepting the apology. The man probably did have a reason. Not a good one, based on the way the man's mind seemed to be working these days, and certainly nothing that would excuse his actions but a reason why he'd thought it was a good idea nonetheless.

"Not that. I... I'm so sorry, Tadashi, but your brother, Hiro... He's dead."

Tadashi stiffened in the older man's arms. He was lying. He had to be. He didn't even realize the whispered, "No," was his own until the professor replied to it.

"I saw him out joy-riding with your friends from college. You know, the group with the weird nicknames. They were doing insane things like high-speed corners and out-racing the trains. The car ended up in the bay and I didn't see anyone come up."

Tadashi stood there as the other man continued to hug his stiff form, his hands fisting. Callaghan had been there. The microbots were water-proof. And if it had actually happened, if Callaghan wasn't lying... The punch took them both by surprise.

Callaghan touched his split lip with an odd expression, as if he'd had the emotions shocked out of him, even as the microbots quickly restrained Tadashi before he could try again.

"You bastard! You were there! You could've saved them! You could have saved him!" Tadashi screamed as he struggled against the microbots, all his anger and hatred for the man standing in front of him rearing its ugly head. It apparently shook Callaghan out of whatever reverie he'd been in, because the look he shot Tadashi went from surprised to hard very quickly. The microbots' grip suddenly became very painful. Tadashi had to stop struggling lest something in his body break, but he continued to seethe.

"Don't look at me like that!" Callaghan ordered. "I said don't look at me!"

The backhand sent Tadashi's head spinning and a small part of his brain started comparing what he was experiencing versus concussions and whiplash. Then the microbots were moving again. Tadashi was surprised when they deposited him onto the medical bed he'd been sleeping on these past few weeks, but when the microbots held him down as the professor strapped him into place, it made a lot more sense.

"Let me go! You can't do this! You bastard!" Tadashi shouted as he struggled the entire time. But even after the microbots finally moved away, the restraints did their job and held him in place. Then his shouting was stopped when Callaghan forcibly gagged him with a piece of fabric knotted enough to weigh down his tongue while forcing his jaw apart enough to prevent him from gnawing through the part tied behind his head. Tadashi snarled around it, but it muffled any actual words. Then he was blindfolded as well.

Tadashi was starting to panic now. This was worse than the Dark Room. At least in the Dark Room he could move around and do things like count how many footsteps it took to reach one side of the room to the other. When the light was flipped off, even the hint that had managed to sneak past the edges of the blindfold was gone, leaving him in total darkness. The only thing he could really sense was the bed and the restraints.

"Bed time," he heard Robert Callaghan declare before Tadashi heard the door shut and lock. Tadashi had never felt so alone or helpless.

For the next two or three days, or so Tadashi assumed, he was only allowed up from the bed and its restraints for maybe a half-an-hour at what he assumed was three times a day. It was just long enough for Tadashi to be allowed to use the restroom before being force-fed. At no point was he ever unbound as the microbots took the place of the bed's restraints. The gag was only removed long enough for something to be shoved into his mouth to eat or for water to be poured down his throat. The blindfold was never removed at all. And Robert Callaghan remained silent the entire time, even after Tadashi had resorted to begging for forgiveness the moment the gag was removed, even if only so he could heard the sound of his own voice.

The sensory deprivation was hell. With nothing but the bed and restraints to keep him grounded, his brain started making stuff up, mostly random sounds and brief flashes of images. Sometimes he wondered if he was actually being pulled out of bed at all or if he was just imagining things. Only the fact he wasn't dying of dehydration suggested it was real but, with no real way to tell the passage of time, it was easy to convince himself it had only been a few hours and not actually days and that it was possible he was just imagining it had happened.

Then one of the times he was having water poured down his throat, a human hand came to hold his head in place. Tadashi whined as much as he could while trying to drink as fast as he could lest he drown and, when the bottle was pulled away in response to the noise he made, Tadashi turned his head so he could press a cheek against the hand.

"Please," Tadashi begged as the thumb traced his cheekbone and the fingers threaded through his hair. There was a human sigh.

"I'm almost done. One more piece of the portal still needs to be moved, but then it'll be ready, and just in time for the grand opening. Krei's new building is going to be a pit by the time I'm done."

"No. Please!" Tadashi urged, struggling again. The gag was pushed back into his mouth while Callaghan whispered, "Hush." Tadashi started to cry as a gentle kiss was pressed to his forehead. Then he was restrained back onto the bed and left alone again. And Tadashi realized in terror that he had no clue what Callaghan planned to do with him once he was done with Krei.

Notes: Tadashi knowing Abigail is originally from Becky Blue Eyes, although it's definitely worked its way into my own headcanon by this point. Next part should be up just after Christmas. :)