Eric sees Shawn kiss Topanga at Chubbies and tells Cory. It turns out there was actually a good reason for this: Topanga is moving to Pittsburgh with her parents. Cory cannot, and will not, believe this under any circumstances. Shawn also tells him that Topanga will not leave, referencing some TV shows in the process. But, at the end of the episode, Topanga does in fact leave, and Cory is left heart-broken.
A sad episode with a good, interesting plot. It is also the first 2-parter episode of the series. It was a very special episode and was handled well.