In the back of his mind, Tony knew that something wasn't right. That punching Captain America, trying to kill Steve Rogers, was wrong. Part of him remembered all of the different times when they had saved each other's lives. How they had joined together to tease Thor about his hammer, or worked together to take care of their team. Then Captain America would land a punch, or shout for Bucky to run, and all his thoughts about their past friendship would vanish.
Tony had watched, been unable to look away as the tape played, showing the Winter Soldier calmly choking his mother. His mother, who had dealt with all of his quirks and issues without complaint, who had been the one person in his life to love Tony for who he was, and not what he could give.
Knowing that Bucky was the reason that she was gone, the reason that she had never gotten a chance to see the man Tony had become, hurt. He could feel the ache deep in his bones, and it was far worse than any battle injury.
"Go, get out of here!" He heard Cap yell, and Tony reversed directions, trying to hit Barnes with his phasor.
As Tony readied himself for another shot, Cap jumped in his way. "It wasn't him Tony; Hydra had control of his mind."
Maybe Tony could have forgiven Cap for not signing the accords, he might have even been able to forgive Steve for not telling him about his parents' death, but he couldn't forgive Captain America for defending the man who had personally strangled his mother.
"Move," Was Tony's only reply.
Did Captain America know what it was like to watch his parents bleed out while standing next to the man who had done it? That monster, Barnes, had killed his parents and never even given them a second thought. He hadn't even had the guts to look Tony's mother in the eye as he drained her life away.
The more Tony thought about it, the more he wanted to punch something. And if that something happened to be a star-spangled super soldier, well, he should have gotten out of the way.
Tony made his way to where Barnes was trying to flee through the opening in the roof. He wasn't going to let that man escape, not before he paid for what he had done. Using one of his rockets, he blasted the lid shut, cutting off Barnes escape route, and giving Tony the opportunity to grab the soldier around the neck.
As they hovered above the ground, Tony asked the question burning in his mind.
"Do you even remember them?"
"All of them." Was the man's only reply, and they fell through the air.
Mid fall, Captain America jumped towards them from one of the shelves, separating Tony and Barnes.
Tony tumbled with the Captain into a different part of the bunker. He climbed over the cement separating them, watching as Captain America struggled to his feet, wishing that he would just stay down, that this nightmare would end. That Tony would wake up, and find that it was all just a horrible dream.
The two stared at each other, than Cap spoke. "This isn't going to change anything."
"I don't care, he killed my mom."
The Winter Soldier had to pay. Tony needed him to pay. After all, wasn't that what Avengers were supposed to do? Avenge things like his parents dying far before he was ready?
Tony attacked, and blow followed blow. Sometimes he was punching Bucky, a face from his nightmares; sometimes it was Cap, his once trusted ally. Never a friend, no true friend of his would fight against him to protect a man that deserved to die.
They fought back like the super soldiers they were, teaming up against him, moving with a harmony that he and Cap had never quite achieved. He lost track of who he was fighting, all of it became a blur. Sometimes it was a silver arm punching him; sometimes he was getting whacked by that stupid, red, white, and blue shield. With a quick analysis from Friday, he finally found a weak spot in their defenses, and blasted Cap with his phasors, sending him flying into the far corner of the room.
Bucky continued fighting, like a man possessed. Gone was the cool, well trained assassin, and in his place was a scrappy kid from Brooklyn, who was terrified of losing the one thing he could hold on to. Tony felt his back hit the wall as the assassin pinned him there, silver fingers clawing at his chest, trying to get to the arch reactor. Desperate, Tony tried to hit him with one of his lasers. He missed Barnes instead blasting a line into the ceiling.
Above them the building rumbled, both men stopped glancing to the ceiling. Something shifted up above, and the ceiling above Cap, weakened by Tony's lasers, collapsed.