The Big Bang Theory's sixth season sees Howard return from space and adjust to normal, married life on earth. Sheldon and Amy's unique relationship continues to progress, though at a slower pace than Amy wants. Leonard and Penny's relationship is business as usual, with Leonard once again proposing to Penny. Meanwhile, Raj finally meets a girl and enters a (somewhat) stable relationship, the demise of which leads to unexpected progress for Raj.
The season starts with Howard still in space, where he must figure out how to break the news to his mother that he'll be moving in with Bernadette. When Howard returns from space, he must adjust not only to married life but life back as a civilian. Initially, he struggles to move on from his space mission, bringing it up at every opportunity, as he fears it's the last great thing he will ever do.
The Big Bang Theory