Throughout the war, Cap and Bucky fought alongside infantry and with a group of heroes known as the Invaders, as well as other groups of younger heroes. In the closing months of World War II, Captain America and Bucky were both presumed dead in an explosion over the English Channel.
It was eventually learned that Bucky was revived and brainwashed by the Soviets as the assassin Winter Soldier. With the help of Captain America, he recovered his memories. Following the apparent murder of Steve Rogers, Bucky took the mantle of Captain America, remaining at this position even after Rogers' return. After being almost killed by the Red Skull's daughter, he decided to fake his death and secretly return to his role as the Winter Soldier, with his lover Black Widow.