Springfield is in an uproar after Principal Skinner makes a sexist comment at the end of an Itchy and Scratchy musical. Principal Skinner is replaced by Melanie Upfoot, a women's educational expert, who decides to divide the school into two different schools: one for boys, and one for girls. Studious Lisa soon becomes frustrated when she isn't learning anything from "girls' school." When the Principal refuses to allow her to take math at the boys' school, Lisa decides to dress up as a boy. While Bart teaches her the ropes of boyhood, Lisa wins the math award at the Student Achievement Awards and learns what it's really like to be a part of the "boys' club" .