The guys search for a perfect Valentine’s Day gift for their significant others; Stuart and Raj host a “lonely people” party at the comic book store.

When Sheldon is accused of sexual harassment, he ends up getting Raj, Leonard and Wolowitz in trouble.

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

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