Season synopsis
Contains spoilers for this season and earlier MCU stories.
Sam Wilson gives Steve Rogers’s shield to a museum rather than become Captain America, only for the government to hand it to decorated soldier John Walker. Bucky Barnes considers that surrender a betrayal of Steve’s judgment. The two reluctantly work together against the Flag Smashers, led by Karli Morgenthau, whose campaign against borders and the displacement of people after the Blip grows increasingly violent. Their unexpected strength comes from recreated super-soldier serum. Bucky introduces Sam to Isaiah Bradley, a Black veteran whose own service as a super soldier was rewarded with imprisonment and experimentation.
Bucky frees Helmut Zemo to help trace the serum, taking the group to Madripoor and a reunion with fugitive Sharon Carter. Their investigation uncovers scientist Wilfred Nagel’s work for the mysterious Power Broker. Zemo kills Nagel and later destroys most of the remaining serum, but Walker secretly takes a dose. After Karli kills Walker’s partner Lemar Hoskins, Walker publicly beats a Flag Smasher to death with the shield. Sam and Bucky defeat him and reclaim it. Stripped of his title, Walker is approached by Valentina Allegra de Fontaine, while Bucky hands Zemo over to the Wakandans.
Sam accepts the mantle and arrives in a Wakandan-made Captain America suit when the Flag Smashers attack a repatriation conference in New York. The heroes rescue the officials, but Sharon, revealed as the Power Broker, shoots Karli dead. Sam challenges the politicians to address the suffering behind her movement. Afterwards, Bucky tells Yori that he killed his son as the Winter Soldier, and Sam secures public recognition for Isaiah in the Captain America exhibition. Walker becomes U.S. Agent. Sharon receives a pardon and immediately plans to sell the government secrets and resources she can access again.