The Separation Oscillation
Season 9, Episode 2 - Aired September 28, 2015

As Leonard and Penny struggle with the revelation he kissed another woman, Leonard goes to meet the woman in question, Mandy, in a bid to show Penny there's nothing to worry about. Meanwhile, Sheldon films an episode of Fun with Flags alone following his break-up with Amy, who is angered by Sheldon's thinly veiled comments about their recent split.