The movie starts with a series of newsreels and clips showing the rise of the Third Reich. Hitler quickly conquers most of Europe but the US has still not intervened. Then we see clips of the Japanese attack on Pearl Harbor. Next we're in a slummy apartment of Steve Rogers, a (literally) starving artist, just barely getting by during the Great Depression. The FDR Pearl Harbor speech is playing over the radio as we see various patriotic artwork. Scrawny, malnourished Steve Rogers is listening intently about the Attack on Pearl Harbor and is enraged. Right away, he grabs his coat and runs out to go enlist in the Army. As he approaches the recruiters' station, he sees a long line of men going around the corner, waiting to sign up. He gets in line and waits patiently. When it's finally his turn, he tells them he'd like to join the army. The recruiter turns him down because he's too unhealthy to join. He pleads with the recruiter, but eventually, he has to walk away disappointed.
Steve, now depressed, goes to the movies to watch the latest news on the war front. He watches all the terrible atrocities that the Axis powers are wreaking on the world and he is enraged and invigorated. He runs back to the recruiting station and storms in, bypassing the long line and demands that they accept him in the Army. The recruiter continues to say that he is too unhealthy to join. After a big patriotic rant, Steve becomes belligerent and angry and there are a few soldiers that try to restrain him and escort him out of the station but he keeps resisting. He demands that they allow him to fight for his country. A high ranking officer with an eye patch, overseeing the new recruits, notices his persistence and patriotism so he orders the soldiers to stop. He introduces himself as Colonel Nicolas Fury (this is the father of Samuel L. Jackson's Nick Fury and looks like the Classic Nick Fury). He takes Steve aside and after a brief conversation, he sees how willing Steve is to serve his country so he mentions a special government program called Rebirth.
Steve becomes a candidate and is put through rigorous elimination process (which includes basic training) until he is finally chosen to become the first human test subject. After injected with the Super Soldier serum, the he feels it working instantly.The scientist oversee a quick demonstration of his new-found strength and deem the experiment a success. Just as they decide to prepare for mass production, the creator of the formula is assassinated by a Nazi spy. Steve Rogers immediately kills the spy but the damage is done and the formula is gone. With Steve being the only Super Soldier, the military decides that rather than put him on the front lines, they will use him for special missions against Hitler's most powerful and dangerous forces.
Steve Rogers would not fight as himself but as a symbol of America used to inspire the nation and raise morale to keep the troops rallied up and ready to fight. Steve showed them sketches he did of a costume with an American flag motif so they had an outfit made up for him immediately. Meanwhile, he was introduced to the President to show him America's new weapon against the Axis Powers. The President was impressed and presented Steve with a special, indestructible shield made by Dr. Stark. He finally donned the mantle of Captain America.
Captain America is first assigned to rescue a group of POW's from an SS base. He is aided by his own squad of troops assigned to him for back up. One of the soldier's is young Pvt. James Buchanan Barnes aka "Bucky". Together they successfully fight off (kill) the German Soldiers and rescue the squad and POW's. Captain America and his squad of what he calls his "Avengers" (because of Pearl Harbor) manage to successfully pull off dangerous missions all over the world for the Allies from the Pacific to Africa. He and Bucky become like brothers over the missions and even trusts him with his secret identity. All missions are linked to a German SS Trooper known as the Red Skull. The Red Skull is Hitler's best weapon against the Allies and Captain America finally tracks him down in Russia. After D-Day, the Russians are closing in on Hitler in Germany and the Red Skull is the only one who can stop them. Captain's mission is to eliminate the Red Skull. After a big bloody battle between the Avengers and German troops, Captain is face to face with the Red Skull and they fight. Red Skull realizes he can't beat Captain so he tries to escape by jet with a prototype explosive similar to an atom bomb. Captain jumps into the jet as it flies North. Captain America and Red Skull continue to fight. In while fighting, Captain America arms the bomb to explode while in the air to destroy it out of harms way. Captain then jumps out of the plane in a desperate attempt to survive and lands in the icy waters of the Arctic Circle. He then climbs onto a small glacier where he watches the plane explode. The debris falls on the glacier and flips it over causing Captain America to be frozen and embedded in the glacier as it drifts through the water. The movie ends about 60 years later with search team from S.H.I.E.L.D. digging through the ice as one of the agents says "Mr.Fury, we found him."