After Leonard and Sheldon have a heated argument about what Sheldon sees as Leonard making a major breach in the roommate agreement, Leonard takes refuge at Penny's apartment. Despite the seriousness of the argument, Leonard assures Penny that Sheldon was much more difficult to live with when Leonard first moved in. Leonard recounts to her his first meeting with Sheldon seven years earlier when Leonard answered Sheldon's advertisement looking for a new roommate. He also recounts Howard and Raj's first encounters with Sheldon, what happened to the now broken elevator which was working when Leonard first moved in, and why Leonard decided to stay despite Sheldon being such a difficult and unusual roommate.