Selma decides to marry her prison pen-pal, who is none other then the infamous Sideshow Bob. Bob appears to have changed for the better, but Bart remains skeptical about the whole thing and thinks Bob is planning something big. In the end, Bart is right, and he tells the whole Simpson family Bob's plan was to murder Selma and get her money. In the end Bob goes back to jail and everything is better.
Another good episode, I feel in the classic era Bob episodes are generally the best of their season. This one might not have been best of season 3, but it is great no doubt