When D.W. has a brush with poison ivy, Buster tells a story about how he once got asthma. When Buster learns he has asthma, his friends start treating him differently, thinking that Buster needed special attention. Buster educates his friends by doing a science project about asthma. Muffy and Francine play several tricks on Arthur, Buster, Binky, and the Brain and invite them to a costume party at a haunted house. The boys decide to get vengeance on the girls at the party while Muffy and Francine are ready with another trick. They call off all pranks when they discover a real ghost.