An orphaned teen hits the road with a mysterious robot to find her long-lost brother, teaming up with a smuggler and his wisecracking sidekick.

With many people fearing the actions of super heroes, the government decides to push for the Hero Registration Act, a law that limits a hero's actions. This results in a division in The Avengers. Iron Man stands with this Act, claiming that their actions must be kept in check otherwise cities will continue to be destroyed, but Captain America feels that saving the world is daring enough and that they cannot rely on the government to protect the world. This escalates into an all-out war between Team Iron Man (Iron Man, Black Panther, Vision, Black Widow, War Machine, and Spiderman) and Team Captain America (Captain America, Bucky Barnes, Falcon, Sharon Carter, Scarlet Witch, Hawkeye, and Ant Man) while a new villain emerges.

For Steve Rogers, awakening after decades of suspended animation involves more than catching up on pop culture; it also means that this old school idealist must face a world of subtler threats and difficult moral complexities. That comes clear when Director Nick Fury is killed by the mysterious assassin, the Winter Soldier, but not before warning Rogers that SHIELD has been subverted by its enemies. When Rogers acts on Fury's warning to trust no one there, he is branded as a traitor by the organization. Now a fugitive, Captain America must get to the bottom of this deadly mystery with the help of the Black Widow and his new friend, The Falcon. However, the battle will be costly for the Sentinel of Liberty, with Rogers finding enemies where he least expects them while learning that the Winter Soldier looks disturbingly familiar.