On the Season 7 Finale of The Big Bang Theory, Leonard and Penny tell the rest of the gang that they are engaged, and everyone rushes around to congratulate them. Then, Raj says that he thought the big news was going to be that he had sex with Emily, and everyone rushes around to congratulate him instead. When Leonard asks what the deal is, Bernadette quips that they get engaged all the time, but Raj having sex is something that never happens.
At lunch, Raj is bragging to Leonard and Howard about having sex, when Sheldon joins them and starts complaining about the university not allowing him to switch his field. Back at Howard’s mom house, Howard and Bernadette are dealing with babysitting Howard’s mom. Howard suggests they use their vacation time to watch his mom, and Bernadette jokes that she wants a divorce.
Leonard calls his mom to tell her that he’s engaged to Penny, but his mom tells him that Sheldon already told her. While Leonard’s mom says she had her misgivings about Penny, Sheldon spoke very highly of her, and if she’s good enough for Sheldon, then she’s good enough for her.
Penny is on the phone telling her mom that she’s engaged to Leonard. Penny responds that she’s not pregnant, which is a first for their family. Amy asks what the living arrangements will be after they get married, but Penny says she doesn’t know, because she doesn’t have a job. Bernadette offers Penny a job taking care of Howard’s mom, which she reluctantly takes. The scene flashes to Penny taking off gloves and quitting the job.
Leonard sits down with Sheldon to talk about the living arrangements after he gets married, and Sheldon says that he will allow Penny to live there one day a week. Leonard explains he was thinking more of him and Penny living together without Sheldon. When Leonard suggests that Sheldon could move across the hall, Sheldon asks if he had marijuana. Sheldon accuses Leonard of putting his future bride’s happiness above Sheldon’s happiness, and Leonard responds, “Well, yeah.”
Sheldon is complaining to Amy about the university making him go back to string theory and Leonard suggesting he move out. Amy gives Sheldon some Strawberry Quik to make him feel better, and Amy points out all the things that bother Sheldon about Leonard. Amy suggests that maybe Sheldon could live with her, but Sheldon goes on a rant and storms off.
Amy goes and tells Leonard and Penny that Sheldon’s is really mad that Leonard suggested Sheldon move out. Amy sits down and joins Leonard and Penny, and Leonard hints that they want to be alone, before Penny finally tells Amy to get out.
Sheldon goes to see Stuart at the comic book store, but the comic book store has been destroyed in a fire. Stuart says he’s going to be closed for a while, and Sheldon offers to purchase a comic to help him get back on his feet. When Stuart is sarcastic, Sheldon storms out saying he’s not the only one whose day has been a disaster.
Raj and Howard are helping Stuart clean up the comic book shop. Stuart asks to stay with Raj, but Raj says Emily could be staying over. Howard says he has a place for Stuart to say.
Leonard and Penny go to see Sheldon at the train station. Sheldon plans to leave. When Penny asks where he’s going, Sheldon says it doesn’t matter. Leonard offers to take Sheldon to Legoland if he’ll come home, but Sheldon says he need to get away and think. Penny calls Leonard over and tells him that maybe they need to let Sheldon go. Leonard is worried, but Penny says he’ll be ok.
Leonard tells Sheldon that if he really needs to do this that he won’t stand in his way. Sheldon says that he does. Before leaving Leonard tells Sheldon that he’s going to miss him, and Sheldon responds, “Of course you are.”
Howard and Bernadette are sitting on the couch at Howard's mom house, when Stuart comes down and tells them they can go. When Bernadette asks if Howard’s mom isn’t too much for him, Stuart tells them that the job is a dream come true for him. While Howard and Bernadette feel Stuart’s reaction seems unnatural, they have no problem leaving.
Sheldon calls to check in with Amy, and Amy says that Sheldon sounds like he is doing well. After Penny says that she thinks the change might be for the best for Sheldon, Leonard starts to say something, but Amy starts hitting Leonard with a pillow and screaming at him for letting Sheldon go.