Sheldon has a revelation when he realizes why a song was stuck in his head. Also, Amy invites Dave over for dinner despite their previously awkward date, and Wolowitz and…

Wil Wheaton interviews Sheldon for a Star Trek documentary where he reveals the ring and his plan to propose to Amy. Bernadette wants to start renovating the house and the…

Sheldon, Wolowitz and Koothrappali post an online advertisement to find Sheldon a new girlfriend. Also, when Amy is coy with details about a guy she is dating, Penny and Bernadette…