Aunt Selma realizes that she might wind up dying all alone and thinks that having a baby can relieve her loneliness. To test her maternal instincts, she takes Bart and Lisa to Duff Gardens, an amusement park, where she realizes that parenthood isn't all it's cracked up to be. At the park, Lisa gets high by drinking the water in the Little Land of Duff ride, and Bart misbehaves in his own unique way. Shaken by the experience, Selma is pleased to have no kids of her own and accepts her life and everyone in it, including Jub Jub, her pet iguana.