One of the Avengers' greatest foes, Baron Zemo, formed the Thunderbolts as a team of ostensible heroes who were truly super-villains in disguise. When the team's true motives were exposed, some of the Thunderbolts remained together to try to make it as heroes. Now Zemo has a new plot that teams him with the hordes of Hydra--and the Avengers and the Thunderbolts must put aside their differences and work together to stop the greater threat of Zemo!