Steve Rogers struggles to embrace his role in the modern world and battles a new threat from old history: the Soviet agent known as the Winter Soldier.
Two years after the Battle of New York, Steve Rogers a.k.a Captain America is out on a jog in Washington D.C. While jogging he is frequently passing by a man who later introduces himself as Samuel Wilson telling him that he used to work in the army but now he works in the debriefing section. After the jog, Sam and Steve have a chat about how Steve is adapting to the new world. Natasha Romanoff then arrives to take Steve with her on a mission. The mission at hand is to rescue the hostages of a pirate-hijacked S.H.I.E.L.D. ship. Cap, Agent Rumlow, Romanoff and his men fight the pirates and rescue the hostages. But as it turns out Natasha had gotten a secret mission which was to receive some S.H.I.E.L.D data from the ship, to a USB-stick arousing suspicion from Steve.
When back at the Triskelion, Steve is angry with Nick Fury for lying to him. Fury then takes him to the basement where there are several Helicarriers and he introduces Steve to the Insight Program. He tells Steve that S.H.I.E.L.D takes the world as it is, not as they like it to be. They are going to use the Helicarriers to fight threats before they even happened. Cap then says that, "This is not freedom. This is fear..."
Later Steve visits the Captain America museum and also visits Peggy Carter in a retirement home, now past 90 years old. He also meets with Samuel Wilson again after watching him during the end of his debriefing session. Meanwhile, Fury discovers that the data on the USB is inaccessible. He tells this to Alexander Pierce, who just had a talk with the World Security Council about whether or not to let Fury continue to run S.H.I.E.L.D. Fury is on his way away from the Triskelion when he is attacked by fake cops. He defeats them but is stopped when a masked man shoots a magnetic bomb under Fury's car, flipping it over. But before the masked man gets to Fury, he manages to drill a hole in the ground with a gadget and escapes. Steve arrives to his apartment after talking to his neighbor, but gets suspicious when he hears that his stereo is still on. Steve sneaks in through the window and finds Fury sitting on his couch. He tells Steve that his wife kicked him out and that they might be overheard by someone, before getting shot several times in his back through the wall. He gives the USB to Steve and tells him not to trust anyone, before he falls unconscious. Steve's neighbor smashes in the door revealing herself to be Agent 13. Steve finds the gunman and starts to chase him. He throws his shield at the masked man, but surprisingly the man catches the shield with his cybernetic arm and throws it back. He then jumps of the building and disappears.
Fury is taken to a hospital, but his heart stops and he couldn't get revived. He's taken away and Agent Maria Hill asks to take care of the body. Agent Rumlow tells Cap that he is wanted for a hearing. He quickly hides the USB in a vending machine and leaves. When he arrives at the Triskelion he is questioned by Alexander Pierce who says he is one of Nick's oldest friends and wants to know who killed him. He also says that he and Nick were realists and that to build a new world sometimes meant tearing the old one down. Cap doesn’t trust Pierce and tells him none of what Fury said. He leaves Alexander to go to the hospital. While in the elevator, it starts to fill up with people and he soon realizes that they are there to take him down. He asks if anyone wants to get out and then the fight begins. It's hard, but Cap manages to knock out all his attackers, before jumping out the elevator to avoid arrest. After surviving the fall, he drives away on a motorcycle. A roadblock is set up for him and he also gets stopped by a Quinjet. However, he gets past both.
It is later revealed that Pierce is working with the masked man when he shoots his cleaner for seeing him together with the masked man. Steve later arrives at the hospital where he notices that the USB is gone. Natasha has taken it and he angrily asks her what she knows about all that has happened. She tells him that the masked man is a spy known as the Winter Soldier and she had encountered him once before. She decides to follow Cap. They go to an internet café to see if there is any valuable information on it. But they, as Fury did, find nothing. However, they did find the location where the USB could be unlocked. Rumlow and his team try to find them, but fail to do so. They steal a car and drive to the location while talking about the good old days. When they arrive Steve realizes that they are at the old training facility where he had trained during WW2. They find a secret storage room full of old computers inside a S.H.I.E.L.D office. There they find a more modern looking USB slot and they put the USB in. The computers power up and someone starts to talk to them. It is Arnim Zola who tells them that he was recruited by S.H.I.E.L.D after WW2 and that he helped to rebuild Hydra inside S.H.I.E.L.D. But in the 70's when he got the news that his body was un-savable S.H.I.E.L.D, still needing his help, transferred his mind into a software. He had been working on an algorithm that HYDRA wanted. He told them that some of the deaths of S.H.I.E.L.D leaders had been due to Hydra, showing them a picture of Howard Stark, implying that his death might not have been an accident. He was also involved in the Winter Soldier program. But before Rogers and Romanoff can get any more information out of Zola S.H.I.E.L.D shows up and blows up the place. They survive the explosion and seek refuge with Sam Wilson. Sam tells them that he was part of a military project called Falcon, a testing of a new form of winged Jet-Packs. They head back to D.C to talk to Agent Jasper Sitwell who is also working for Hydra. Sitwell just had a meeting with Senator Stern, who before saying goodbye whispered Hail Hydra. Sam Wilson calls Sitwell and forces him up on the roof of a tall building together with Natasha and Steve they get him to tell them that Zola's algorithm could calculate if a person would be a threat in the future. He also tells them that Hydra are going to use Project Insight as a weapon to eliminate what they see as threats against the world, mentioning Tony Stark, Bruce Banner and Stephen Strange. This, though, would also mean that millions of innocent people would die. The gang leaves but is attacked by the Winter Soldier and his men. A battle breaks out and as Cap and the Winter Soldier fight his mask is broken and it is revealed that he is Bucky Barnes. Cap says Bucky?, but Bucky doesn't know who that is and Cap, Black Widow and Sam are taken into custody. While in the prison van, one of the guards stuns the other one and reveals herself to be Maria Hill. She then uses the drill gadget to escape with the gang.
Agent Hill takes them to a secret facility where Nick Fury is recovering, revealing that he didn't die, even though he was severely injured. He had taken a anti-stress serum, developed by Bruce Banner, that lowered his heartbeat to only one beat per minute so that he would appear dead. Hill and Fury tell them that Project Insight is only hours away and that they have to act quickly. The Helicarriers would hover in a triangle, connected, targeting all its targets before firing. The only way to prevent this is to use three special chips that alter the helicarriers' program. Cap had lost his suit earlier so he needed to break in to the Captain America exhibit at the Smithsonian museum and steal the one that was on display.
The Winter Soldier is being prepared for battle but he starts to ask who Bucky is. Hydra decides he knows too much about his past and they brainwash him again. He gets a flashback showing how Hydra's Russian division found him in suspended animation after falling of the train. We then learn that Doctor Zola had amputated his destroyed left-arm and changed it with a cybernetic one. He also remembers how he where put in Kryo-tanks between his missions so that he would not get old. The members of the World Security Council arrive at the Triskelion. They are given one device each to put on their collar that will grant them access to anywhere in the Triskelion. They then all walk up to Alexander Pierce's office. Captain America and Sam, a.k.a The Falcon, break in and take control of the microphones. They tell the staff that there are traitors in S.H.I.E.L.D and that Alexander Pierce is one of them and that they cannot initiate Project Insight. Rumlow and his men walk in to the control room and threaten to shoot the guy in charge if he doesn't get the Helicarriers in the air. But agent 13 intervenes and a gunfight breaks out. Rumlow still manages to get the Helicarriers in the air.
Pierce pulls a gun at a WSC member but Agent Romanoff, disguised as a WSC member, stops him. She then calls for Fury who is a S.H.I.E.L.D agent of the highest degree, and since two S.H.I.E.L.D agents of the highest degree are needed to stop Project Insight she asks Pierce to help them. Fury states that Pierce probably erased all traces of Fury being the director of S.H.I.E.L.D, but not on the eye scan since, quite recently, Fury changed the eyescan picture from the picture of his working eye to the picture of his damaged eye. Romanoff then spreads classified documents with all of her and his secrets on the net. Pierce tries to escape, activating the devices on the WSC members' collars that kills them and holds Romanoff hostage. Romanoff disables the device momentarily, giving Fury the chance to shoot Pierce dead. They manage to put the chips, with some hardship, for two of the Helicarriers in the right place, but when Falcon is going for the last one his jet-pack is damaged by the Winter Soldier and he is forced to skydive down to the Triskelion where he gets caught up in a fistfight with Agent Rumlow. Now it's all on Cap. He is about to put the chip in place before he is confronted by Bucky. They fight and during the fight Cap tries to convince Bucky that he was good once upon a time. As he tries to get the chip in place with only seconds left before Project Insight will initiate he gets shot multiple times by Bucky. He manages, though, and Agent Hill can take control of the other Helicarriers and shoots down the Project Insight ones. Before Steve passes out he promises Bucky to be with him until the end, a promise that Bucky had given Steve decades ago. Then Cap falls into the water beneath and is about to drown when a hand grabs him and drags him out of the water. It is Bucky, who then disappears. One of the Helicarriers crashes into the Triskelion and causes it to collapse. Falcon jumps out of the window to the 41st floor and is saved by that much by Fury and Romanoff. Rumlow is buried under rubble, but is later seen being taken care of by doctors. When Steve wakes up some time later a lot of new stuff has happened. S.H.I.E.L.D has gone through some major changes. Nick Fury is officially dead and he has destroyed all evidence of being alive, even ditching the eye-patch for sunglasses. And if somebody asked what happened with Fury, he wants Cap to answer that he is dead. Natasha goes to a hearing where they asked why she shouldn't go to jail for what she had done. She said that it was because they still need her. Now that her secrets were revealed she needs a new identity. Cap decides to start looking, with the help of The Falcon, for Bucky, so that he can convince him of who he really is. In the mid-credits scene we see Baron Wolfgang von Strucker in a Hydra base in possession of the Chitauri Scepter. He states that though Hydras spies in S.H.I.E.L.D may be gone, there are followers all around the world. He then walks over to a pair of cells. He stops in front of them and says, 'It's not a world of spies anymore. Not even a world of heroes. This is the Age of Miracles. He also states that, 'There is nothing more horrifying ... than a miracle'. One of the cells contains a man who is running around at a tremendous speed. The other one contains a woman who levitates a few books, before she lets a beam of energy explode from her hand. Though not mentioned by name, one could figure out that this is indeed Pietro and Wanda Maximoff, otherwise known as Quicksilver and Scarlet Witch.
In the post credit-scene we see Bucky, now in normal clothes, walking around in the Captain America exhibit at the Smithsonian museum. He then stops to read about himself.
- Chris Evans - Steve Rogers
- Scarlett Johansson - Natasha Romanoff
- Anthony Mackie - Sam Wilson
- Samuel L. Jackson - Nick Fury
- Robert Redford - Alexander Pierce
- Sebastian Stan - James 'Bucky' Barnes
- Cobie Smulders - Maria Hill
- Emily VanCamp - Sharon Carter
- Frank Grillo - Brock Rumlow
- Maximiliano Hernandez - Jasper Sitwell
- Toby Jones - Arnim Zola
- Hayley Atwell - Peggy Carter
- Dominic Cooper - Howard Stark
- Garry Shandling - Senator Stern