Here is the official synopsis of the movie:
“Captain America: The First Avenger” will focus on the early days of the Marvel Universe when Steve Rogers (Chris Evans) volunteers to participate in an experimental program that turns him into the Super Soldier known as Captain America. As Captain America, Rogers joins forces with Bucky Barnes (Sebastian Stan) and Peggy Carter (Hayley Atwell) to wage war on the evil HYDRA organization, led by the villainous Red Skull (Hugo Weaving.)
Captain America: The First Avenger opens worldwide on July 22nd 2011.
Watch the full trailer here: