"My Big Fat Geek Wedding" is the seventeenth episode of Season 15.
After leaving Principal Skinner at the altar, Mrs. Krabappel falls for Comic Book Guy and they plan a Star Trek-like wedding. Principal Skinner plans to prevent it.
At school, a ball is thrown very high and lands straight into the grass, where Groundskeeper Willie destroys it on his tractor. But, when he sees its pieces coming out, he becomes terrified, thinking that he accidentally killed a child (again) and hurries across the road to reach the border, claiming that he is traveling to Venezuela. Not only the announcement is placed about the ball, but it also reveals that love is in the air, as Principal Skinner and Edna Krabappel are finally getting married. They each have their bachelor party, with Mrs. Krabappel having hers at the Simpson house with Duffman and Chief Wiggum as strippers, and Principal Skinner having his at Moe's Tavern with Homer. However, at his party, Skinner admits that he has doubts about marrying Mrs. Krabappel. When the wedding is held at the gymnasium of Springfield Elementary, Edna learns that Skinner does not want to marry her, and runs off from the ceremony, thus making the wedding postponed.
After it is called off, Homer and Marge try to get Skinner and Krabappel to be engaged again, but it is terminated by Homer and Marge's own marriage problems. Eventually, Krabappel returns a wedding gift, but to Comic Book Guy. She finds him to be an interesting man rather than Skinner. Meanwhile, Homer gets Skinner to serenade Krabappel using a band made up of Bart, Milhouse, and Martin, but the plan fails when he finds out that Comic Book Guy and Krabappel are in love.
Later, the family visits the Bi-Monthly Science Fiction Convention (Bi-Mon-Sci-Fi-Con) to confront Comic Book Guy, who is proposing to marry Krabappel after the family sees Futurama creator Matt Groening. Skinner, dressed up as Catwoman (who he thought was Catman), battles Comic Book Guy upon seeing the proposal. Krabappel, however, interrupts their fight to declare that she will not marry either man. When she tells Comic Book Guy how they had fun but are very different, he accepts her decision, although Skinner is still miserable. Later, at the Simpson house, Homer asks Marge to remarry him, which is done in the style of a mock Klingon wedding.