The Roommate Transmogrification

"The Roommate Transmogrification" serves as the fourth-season finale of *The Big Bang Theory*, airing on CBS on May 19, 2011. It is the twenty-fourth episode of the season and the eighty-seventh episode of the series. Aarti Mann appears again as Priya Koothrappali, while Brian George and Alice Amter return as Dr. and Mrs. Koothrappali.

The episode begins at the Cheesecake Factory, where the group mocks Leonard for his lactose intolerance. When Bernadette announces her dissertation has been accepted, earning her a Ph.D. and a high-paying job, Penny joins the others in teasing Howard for being the only non-doctor among them. Later, Bernadette gives Howard an expensive Rolex watch, telling him to let her handle the finances—a comment that unsettles him.

Meanwhile, Leonard and Priya’s loud and astronomically inaccurate sexual roleplay (involving Raj’s Lieutenant Uhura costume) drives Raj out of his own apartment to spend the night at Sheldon’s. The next morning, Leonard apologizes and suggests Raj move in with Sheldon until Priya finds her own place. Raj agrees after Sheldon completes his bureaucratic steps, including a modified temporary roommate agreement and a will. Raj then cooks a fancy dinner to win Sheldon over, and Sheldon is pleased. Penny arrives to borrow their Wi-Fi password, stays for dinner, and gets drunk with Raj. Sheldon goes to bed, and Penny admits she regrets breaking up with Leonard, telling Raj she would pursue him if they weren’t friends.

Priya receives a video call from her parents and tells Leonard to hide in the bedroom, as she still hides their relationship from them. Leonard overhears the Koothrappalis discussing Priya moving back to India the following month. He confronts her, revealing their relationship to her parents and arguing that her move would mean their breakup, making the secret pointless. Later, Sheldon finds Leonard sleeping on the couch after the fight, and Howard arrives after a fight with Bernadette about the watch. Penny wakes up in Leonard’s room, horrified to find herself naked with Raj, realizing they hooked up. She tells him to keep quiet and tries to sneak out with Raj wrapped in a sheet, but the other men see them. Penny insists it’s “not what it looks like,” leaving Sheldon, Leonard, and Howard confused.

On its initial broadcast, the episode was watched by 11.30 million households, making it the fourth leas