Howard crashes Bernadette’s date at a restaurant, pretending to be a waiter. He humiliates himself by spilling food, insulting her date, and revealing he's been following her. Bernadette is furious but later admits she found his jealousy "sweet." They reconcile and kiss.
Sheldon devises a childish but elaborate plan: break into Laughlin's office and fill his filing cabinets with expanding foam. He enlists a reluctant Leonard, Raj, and Howard. At the university, the plan goes awry when Sheldon sets off a silent alarm. Leonard saves them by talking to a security guard, but they leave behind a glove. La Teoria del Big Bang 3x9