Penny is ecstatic to get a minor role on NCIS but is devastated when her scene is cut. While comforting her, Leonard accidentally suggests her scene would have made no difference to her career, which upsets her. She demands he honestly tell her his opinion on her acting, and he admits to believing she has unrealistic ambitions for success. Later realizing his honesty may have hurt Penny, Leonard brings her an offer to audition for a part in the new Star Wars movie by submitting a video. Penny gets drunk and proposes to Leonard after thinking the only good thing in her life is him. Because Penny is upset and drunk, Leonard hesitates to answer, so Penny leaves, and Leonard is left wondering if their relationship might be over. At Howard's advice, Raj and Stuart go to the mall to improve their ability to talk to women but only talk to the security guard. After realizing no-one finds him funny, Sheldon wants to learn to become more humorous and attempts to develop a universal theory of humor. He bores Amy by asking which words she finds funny. Amy meets up with Howard and Bernadette. Bernadette admits to Howard she often fakes a laugh at his jokes.