After preventing an international nuclear disaster caused by Radioactive Man—who manages to escape—the Avengers face criticism regarding the limits of their actions and their lack of responsibility given the power they possess. Amidst this climate of instability, the mysterious European aristocrat Baron Helmut Zemo emerges from the shadows, determined to prove that the Avengers can be defeated.
Secretly, Zemo assembles a group of superpowered criminals: Enchantress, Skurge, Abomination, Crimson Dynamo, Radioactive Man, and Wonder Man, forming the Masters of Evil. More than winning a battle, Zemo wants to destroy the Avengers' symbol, especially Captain America, because of an old connection to Steve Rogers' past.
While Enchantress emotionally manipulates Hulk, transforming him into a threat, Radioactive Man and Absorbing Man expose the destructive potential of Thor's powers. The pressure begins to divide the team: Hank Pym fears that the Avengers are causing more chaos than solutions, leading to conflict with Janet. Meanwhile, Tony Stark and Steve Rogers disagree about leadership and responsibility. Steve confronts ghosts from the past linked to Zemo, while Tony questions whether Iron Man has done more harm than good to the world.
When the Masters of Evil launch coordinated attacks around the globe, the Avengers realize too late that it was all part of a larger plan: to isolate each hero before the final blow. The confrontation culminates in a massive siege in Washington, where Zemo reveals he has studied each member of the team. For the first time, the Avengers face an enemy that relies not only on strength, but on strategy.
