With his friends on dates, Raj must face his loneliness. Also, Wolowitz is caught in an argument between Bernadette and his mom, even while he’s in space.

When Sheldon learns that Penny is thinking about breaking up with Leonard, he tries to intervene. Meanwhile, in space, the other astronauts pick on Howard.

Amy feels threatened when Sheldon hires a young female assistant, and the pressure of being in space takes its toll on Wolowitz.

When Wolowitz returns from space, he doesn’t get the hero’s welcome he expected. Meanwhile, Game Night turns into a battle of the sexes.

The gang celebrates Halloween at Stuart’s comic book store. Meanwhile, Leonard seduces Penny with science.

Sheldon’s relationship with Stephen Hawking is threatened over a game of “Words with Friends,” and Penny secretly enrolls in a class at the local college.

Wolowitz struggles with moving out of his mother’s house. Meanwhile, Sheldon is caught in the middle of an argument between Amy and Wil Wheaton.

Raj and Howard try to to figure out why Sheldon disappears at 2:45 every afternoon; jealousy arises in Penny and Leonard's relationship.