When Robin fears that Barney is cheating on her, she soon discovers that he is spending his evenings with Ted learning everything there is to know on how to date her.

While on a blind date, Ted realizes this is actually his second first date with the same girl, and seven years later they still have nothing in common. Meanwhile, Barney takes Marshall out on the town, much to the dismay of Robin.

When Marshall and the gang finds out that Barney and Robin are hesitant to define their relationship, Lily forces them to confront their biggest fear. Meanwhile, Ted is anxious about teaching his first lecture at Columbia.