[Avengers/Iron Man] We Weren't There (AU)

Synopsis: James Barnes, nicknamed the "Winter Soldier," is baffled. He can't figure out how, after he just went to sleep, his best friend woke up with this new hobby: Steve has a whole litter of little animals. Literally a whole litter, all with the same features: big caramel-colored eyes, fluffy chestnut fur, short arms and legs, and round little bodies. Yes, you, you damn fat rat, get off me! The real version: This is an AU world. The civil war centuries ago was a battle between humans and mutants. There was no Captain America or Iron Man. The mutants lost, and humans put them aboard spaceships and sent them into space to fend for themselves. Steve Rogers is a mutant born in space. Along with his teammates, he leads the mutants back to Earth to take revenge. That team is called the Avengers. Tony is human, born seven hundred years after the mutants returned to Earth. The humans lost the war and became slaves. To save his brother, Steve cuts out a man's heart to use as a "medicine primer." That human is Tony Stark. Tony miraculously survives, and seven years later, he reunites with Steve, formally setting off a war between humans and superhumans. (This can't really be called a product of Captain America: Civil War. It should be more like my own take on the civil war. I haven't read the comics, so I'm not going to get into that. What if Captain America and Iron Man hadn't appeared in the civil war? Then it would just be a brawl between two groups.) Theme: