After Casey Happleton tells him that if he kisses his elbow he will turn into a girl, nine-year-old Marvin experiments and finds himself very confused about his identity.
Marvin is pleased when his teacher asks him to take care of her dog while she's away, but he soon finds that there's more pressure involved than he likes.
Even though they have all come to school in holey clothes, Marvin and his third grade class manage to impress their surprise visitor--the President of the United States.
Two days after Marvin sees a glowing green thing like a flying birthday cake in the night sky, his third-grade class is joined by a mysterious new boy with peculiar behavior.
