Two years after the Battle of New York,^[a] Steve Rogers works in Washington, D.C., for the espionage agency S.H.I.E.L.D., while adjusting to contemporary society. During a mission alongside Agent Natasha Romanoff and S.H.I.E.L.D.’s counter-terrorism S.T.R.I.K.E. team led by Agent Brock Rumlow to free hostages aboard a S.H.I.E.L.D. vessel from pirates led by Georges Batroc, Rogers discovers Romanoff has another assignment: to extract data from the ship’s computers.

Returning to the Triskelion, S.H.I.E.L.D.’s headquarters, Rogers confronts Director Nick Fury and is briefed about Project Insight: three Helicarriers linked to spy satellites, designed to eliminate threats preemptively. Unable to decrypt Romanoff’s data, Fury becomes suspicious about Insight and asks senior S.H.I.E.L.D. official and Secretary of Internal Security Alexander Pierce to delay the project. On his way to rendezvous with Maria Hill, Fury is ambushed by assailants led by an assassin called the Winter Soldier. Escaping to Rogers’ apartment, Fury warns him that S.H.I.E.L.D. is compromised but is shot by the Winter Soldier before handing Rogers a flash drive containing the ship’s data. Fury is pronounced dead during surgery, and Hill recovers the body.

Pierce summons Rogers to the Triskelion. When Rogers withholds Fury’s information, Pierce brands him a fugitive. Hunted by S.T.R.I.K.E., Rogers meets with Romanoff. Using the data, they discover a secret S.H.I.E.L.D. bunker in New Jersey, where they activate a supercomputer containing the preserved consciousness of Arnim Zola. Zola reveals that after being captured by Rogers during World War II,^[b] he was recruited to S.H.I.E.L.D., where he secretly reformed Hydra within its ranks, sowing global chaos using the Winter Soldier as their primary assassin. The pair narrowly escapes death when a S.H.I.E.L.D. missile destroys the bunker, and they realize that Pierce is Hydra’s leader within S.H.I.E.L.D. Rogers and Romanoff enlist the help of VA employee and former USAF pararescueman Sam Wilson, whom Rogers befriended, and acquire a powered “Falcon” wingpack used by Wilson while he was in the Air Force.

They capture S.H.I.E.L.D. agent Jasper Sitwell, a Hydra mole, forcing him to divulge that Zola developed a data mining algorithm that can identify individuals becoming future threats to Hydra. The Insight Helicarriers will sweep the globe, using satellites to identify threats, and eliminating them using automated mounted guns. Sitwell is killed in an ambush by the Winter Soldier, whom Rogers recognizes as Bucky Barnes, his longtime best friend previously thought dead; he had survived due to Zola’s experimentation and has been repeatedly brainwashed and cryogenically frozen to perform Hydra’s missions. Hill manages to extract the trio to a safehouse where Fury, who had faked his death, plans to sabotage the Helicarriers by replacing their controller chips.

After the World Security Council members arrive for the Helicarriers’ launch, Rogers broadcasts Hydra’s plot to everyone at the Triskelion. Romanoff, disguised as one of the Council members, disarms Pierce. Fury arrives and forces Pierce to unlock S.H.I.E.L.D.’s database so Romanoff can leak classified information, exposing Hydra to the public. Following a struggle, Fury fatally shoots Pierce. Rogers and Wilson raid two Helicarriers and replace the controller chips, but Barnes destroys Wilson’s suit and fights Rogers on the third. Rogers fends him off and replaces the final chip, allowing Hill to take control and have the vessels destroy each other.

Rogers refuses to fight Barnes in an attempt to reach his friend, but as the ship collides with the Triskelion, Rogers falls into the Potomac River. Barnes rescues the unconscious Rogers before disappearing into the woods. With S.H.I.E.L.D. in disarray, Romanoff appears before a Senate subcommittee to defend her and Rogers’ actions. Fury, under the cover of his apparent death, heads to Europe to pursue Hydra’s remaining cells. Rogers and Wilson decide to find Barnes, while Rumlow, who was a Hydra agent, is hospitalized following the Triskelion’s destruction.

In a mid-credits scene, at a Hydra lab, Baron Wolfgang von Strucker and his scientists examine an energy-filled scepter and two test subjects: one with superhuman speed, the other with telekinetic powers.^[d] In a post-credits scene, Barnes visits his own memorial at the Smithsonian Institution.