Penny helps Sheldon work on his relationship with Amy when he trivializes one of her accomplishments. Howard is irked by Bernadette's dislike of children.
Leonard and Penny develop a system to ensure their dates go smoothly. Raj finally finds a woman he can talk to - the virtual assistant on his mobile phone.
Leonard signs out of his roommate agreement, reducing himself and Sheldon to mere acquaintances, while Howard tries to think of a cool astronaut nickname for himself.
When the university forces Sheldon to use vacation days, he decides to hang out in Amy's lab. Howard becomes upset when he hears Bernadette wants him to sign a prenuptial agreement.
NASA cancel, and later reinstate Howard's mission into space, coinciding with his wedding. Leonard inadvertently jeopardizes his relationship with Penny.
Raj crashes Sheldon and Amy's second anniversary and interferes in Leonard and Penny's relationship. Howard gets caught in the middle of an argument between Bernadette and his mother.
When Sheldon hires a female grad student to assist him, a jealous Amy asks Penny to help her spy on them. On the space station, Howard begins behaving erratically.
While Raj plans Stuart's Halloween party at the comic book store, Howard annoys the rest of the gang by constantly talking about space, and Penny tries to take more of an interest in Leonard's work.
Howard makes a decision whether or not to move out of his mother's house, while Sheldon is caught in the middle of an argument between Amy and Wil Wheaton.
Leonard feels threatened after hearing about Penny's study partner at school, while Howard and Raj become determined to find out one of Sheldon's secrets.
Howard tries to bond with Bernadette's father during a fishing trip. When Sheldon is obligated to take care of a sick Amy, she finds ways to take advantage of the situation.