In the present day, a Russian oil team discovers a strange derelict in the frozen Arctic wastes. Investigating, they discover a frozen red and blue discus with a white star emblazoned on it.
Seventy years earlier, it was the darkest days of World War II. It is 1942 and the Nazis are on the rise thanks to their new research & development section known as Hydra led by the fanatical Johann Schmidt who has discovered an ancient supernatural artifact known as Tesseract that holds the key of boundless energy that is the cornerstone to Hydra's unstoppable weapons created by Dr. Arnim Zola.
Schmidt has taken on the sobriquet of the Red Skull due to the grotesque alterations to his face as a side effect of experiments he conducted upon himself to enhance his physical abilities. A monster whose face mirrors his twisted soul, the Red Skull is absolutely ruthless and determined to conquer the entire world.
The United States has entered the war on the losing side and Bucky Barnes and his best friend Steve Rogers have applied for military service. Barnes is accepted but sickly and physically frail Steve Rogers is summarily rejected. Despite this rejection, the patriotic Steve is determined to serve and secretly tries applying again and again, failing every single time. After his fifth attempt, his efforts attract the attention of Dr. Abraham Erskine.
Erskine is attempting to perfect the process used by Schmidt to enhance a human to the peak of human performance and offers Rogers a chance which he eagerly accepts. While Rogers and a platoon of men are undergoing basic training under the stern eye of a British officer, Peggy Carter; Erskine's superior, Colonel Chester Phillips is openly contemptuous of his chosen test subject.
Erskine counters that Phillips' candidate might be strong, fast, and obeys orders but is a bully. Phillips sneers at that and proffers that niceness doesn't win wars, wars are won by guts as he grabs a dummy grenade and throws it at the platoon. Everyone in the platoon reacts instantly by ducking and running away for cover. Except for Rogers who charges forward and flings himself onto the dummy grenade, covering it with his own body. Peggy Carter is impressed with his willingness to sacrifice himself and becomes closer to Rogers as a result.
Phillips concedes to Erskine's choice as although physically inferior to the other potential candidates, Rogers' intelligence, determination, and courage shine through and he is chosen to be the first to undergo the process.
Rogers is transformed into the world's first super soldier, but a Hydra assassin murders Erskine who as a safety precaution; has never fully committed the entire formula to paper. Although Rogers is able to avenge the doctor, he is also the last recipient of the process and its only success. However instead of being sent to the front lines, Rogers instead finds himself being used a propaganda tool and mascot in a gaudy costume and is dubbed as Captain America.
But when he learns that Bucky is captured and held behind enemy lines, Rogers disobeys orders and goes AWOL to rescue him with the help of Peggy. Infiltrating Hydra's base, Rogers frees hundreds of prisoners before rescuing Bucky and battling the Red Skull briefly.
Returning victorious, General Phillips is able to convince his superiors that Captain America belongs on the battlefield. Rogers recruits several of the freed prisoners including his friend Bucky to serve as the nucleus of a special strike force dubbed "The Howling Commandos". Rogers is also equipped with a special shield constructed by Howard Stark. This circular shield is composed out of vibranium, a unique alloy that absorbs vibrations and is nearly indestructible.
With the Howling Commandos, Captain America proceeds to beat back Hydra on all fronts; sabotaging their war machines and destroying their hidden bases even as he and Peggy become romantically closer and she promises him a dance one day when they aren't so busy. Pushed to the brink of defeat, Hydra's chief scientist Arnim Zola is being rushed to confer with the Red Skull only to be captured by Captain America and the Howling Commandos which also costs them the life of Bucky Barnes who falls to his death.
Zola reveals critical information that leads to an all out assault on Hydra's Main Base which is preparing for a last strike on the United States with a strategic bomber armed with super-weapons designed to wipe out cities. With the help of Phillips, Peggy, and the Howling Commandos; Captain America is able to force their way through the formidable defenses. Sharing one kiss with Peggy, Captain America leaps onto the Red Skull's bomber as it flies off and fights him aboard. The Tesseract is released during their fight and the Skull grabs it, before it dissolves into thin air before it falls into the ocean.
Discovering that the bomber is locked on target for the United States, Captain America decides that he has to crash the plane in the Arctic. Peggy begs him not to sacrifice himself but Rogers proclaims that he has to do this where the weapons won't be able to harm anyone and asks for a rain check for their dance. Peggy tearfully agrees, demanding that she'll meet him a week later when the radio cuts out leaving only static.
With the Red Skull dead and Hydra crippled, the Nazis find themselves losing badly and the war turns in the Allies' favor. Victorious, the surviving Howling Commandos meet up in a bar and amongst the noisy revelers quietly raise their glasses and salute the Captain even as Howard Stark recovers the Tesseract on the ocean floor, but cannot find any trace of Captain America.
Rogers next awakens in an old fashioned hospital room with a radio playing a live Dodgers game when a young nurse enters the room. Rogers however demands an explanation as he was at that Dodgers' game back in 1941. Panicking, security guards enter the room and Rogers throws them through the wall to find himself on a sound stage replicating the 1940s. Racing through the corridors, he is able to find a door leading to the outside. Fleeing, Rogers realizes that he is in New York City but one barely recognizable when he is soon surrounded by numerous S.H.I.E.L.D Agents and Colonel Nick Fury slowly steps out and introduces himself and that they had created that room to try and break things to him gently. Fury explains that Rogers has been asleep in suspended animation, frozen in the ice and that the year is 2011. Over seventy years after his last mission.
Shocked, Steve looks around lost and brokenly proclaims, "I had a date."
- Chris Evans as Captain America
- Tommy Lee Jones as Chester Phillips
- Hugo Weaving as Red Skull
- Hayley Atwell as Peggy Carter
- Sebastian Stan as James "Bucky" Barnes
- Dominic Cooper as Howard Stark
- Neal McDonough as Timothy "Dum Dum" Dugan
- Derek Luke as Gabe Jones
- Stanley Tucci as Dr. Abraham Erskine
- Kenneth Choi as Jim Morita
- Bruno Ricci as Jacques Dernier
- JJ Feild as James Montgomery Falsworth
- Toby Jones as Arnim Zola
- Richard Armitage as Heinz Kruger
- Samuel L. Jackson as Nick Fury
- Natalie Dormer as Pvt. Lorraine
- Michael Brandon as Senator Brandt