For decades, Captain America was guilt-ridden over the death of his sidekick Bucky in World War II. It turns out he needn't have worried, because Bucky didn't die after all. Hooray! Except he actually befell an even worse fate, having been brainwashed and indoctrinated into becoming the Winter Soldier, a Russian killing machine, doing terrible things that no normal soldier could ever be expected to do. Of course, when Cap discovers the truth he does his best to break the mind control Bucky has been subjected to for years, hoping to return his old friend back to normality. He succeeds, restoring all of Bucky's memories, but the Winter Soldier doesn't thank him: now he has the awareness of all the terrible things he was forced to do, and he tells Cap he should have just killed him instead. As writer Ed Brubaker put it, in bringing Bucky back, he had to replace the tragedy of him being killed in action with something even worse. "Cap tortures Bucky by making him realize everything he did as the Winter Soldier too."
Tom Baker is the Comics Editor at WhatCulture! He's heard all the Doctor Who jokes, but not many about Randall and Hopkirk. He also blogs at http://communibearsilostate.wordpress.com/