Full story
Six months after the Blip, Sam Wilson still doesn't feel ready to be Captain America. He hands the shield Steve Rogers gave him over to the Smithsonian. Bucky Barnes, pardoned by the government, goes to mandatory therapy and tries to make amends for the Winter Soldier's crimes, but still can't bring himself to tell his neighbor Yori the truth. In Louisiana, Sam tries to save the family boat with his sister, Sarah, and runs into a bank that won't trust him.
Days later, the government unveils a new Captain America: John Walker, a decorated soldier, shield in hand. Bucky is furious. At the same time, a group called the Flag Smashers appears, led by Karli Morgenthau, fighting for people displaced after the Blip and packing super-soldier strength. Sam and Bucky meet Isaiah Bradley, a Black super soldier the government locked up and erased from history.
Out of leads, Bucky breaks Helmut Zemo out of prison. The three go to Madripoor, where they find Sharon Carter living as a fugitive and learn that the serum was recreated by a scientist and stolen by Karli. Zemo kills the scientist and destroys most of the doses, but Walker pockets the last one and takes it. The Dora Milaje, led by Ayo, come for Zemo. Then Karli accidentally kills Lemar, Walker's partner. Walker chases down a Flag Smasher and kills him with the shield in front of a crowd.
Sam and Bucky take the shield from Walker, who is discharged and soon approached by Contessa Valentina Allegra de Fontaine. Bucky hands Zemo over to the Dora Milaje. Sam goes home, hears from Isaiah that the country will never accept a Black Captain America, decides to keep the shield anyway and trains with it. Wakanda sends him a new suit.
In the finale in New York, Sam takes up the shield and wings as Captain America to stop a Flag Smashers attack on the Global Repatriation Council. Sharon is revealed as the Power Broker and kills Karli. Sam gives a speech asking the politicians to think about people. Walker becomes U.S. Agent, working for Valentina. Isaiah gets a memorial in the museum. Bucky tells Yori the truth and makes peace with his past. In the post-credits scene, Sharon gets her pardon and goes back to the government with plans of her own. That comes back later.