Searching for Hulk, the Avengers instead find Captain America encased in ice, and seemingly alive. He is defrosted onboard the Quinjet, but after awakening he mistakes the Avengers for agents of HYDRA and confronts them until he escapes swimming to Manhattan and finds a statue in honor to him and Bucky, and begins to realize t what has actually happened.
Meanwhile, Baron Zemo, recently escaped from the Raft, tries to re-take the leadership of HYDRA from Baron Strucker, but when news arrive about Captain America's return, Zemo gives up his leadership claim and only takes Arnim Zola to help him with his revenge. Back in World War 2, Zemo was working on a chemical named Virus X, but Captain America intervened and in the ensuing battle, the virus fell on Zemo's face.
Back at Avengers Mansion, the Avengers explain Cap everything that has happened while he was frozen. The Avengers respond to an emergency, leaving just Captain America and Wasp at the mansion. The emergency turns out to be Zola's Doughboys attacking Ellis island.
Another Doughboy arrives to the mansion and Wasp, with some difficulty, manages to defeat him with her bio-stingers. However, Zemo arrives and knocks her out. Cap doesn't have his shield, as he left it in his room, but Black Panther, who was hidden in the mansion getting info, gives him it back. Captain America regains the upper hand, so Zemo throws a bomb to Wasp and escapes while Cap saves her.
The Avengers are still facing the Doughboys, which combine into a bigger monster. Then Captain America and Wasp come to help, and while Wasp manages some success damaging the huge Doughboy, Cap identifies it as a creation of Arnim Zola. After hearing this, Ant-Man notices Zola's creatures are unstable and the right type of energy (like Wasp's bio-stingers) can disassemble them, so he tells Iron Man to reconfigure his repulsors to shoot in the same frequency, and Doughboy is defeated.
Later, at the mansion, Tony gives Captain America a photo of his father, Howard Stark, alongside Cap and Bucky. He also invites Captain America to join the Avengers, which he accepts. When Cap asks about the Avenger who saved him (referring to Black Panther), Tony gets confused.
- Just like in the comics, the founding Avengers find the frozen Captain America shortly after losing Hulk.
- Baron Zemo's accident with Virus X is a composite event of Heinrich Zemo getting Adhesive X on his mask and Helmut Zemo's disfiguring.
- In the comics, Baron Zemo also decided to take revenge on Captain America shortly after finding about his survival, but he inmediately formed the Masters of Evil. Here, the Masters are Enchantress' idea after Zemo's first revenge attempt fails.