Calvin tries to earn money to buy Stella, the babysitter, a present for her sixteenth birthday because he feels guilty for taking advantage of her allergy to cats.
When his teacher asks him to write a persuasive argument about something he really wants, fourth-grader Calvin creates a unique way to express his desire for a dog.
Fourth-grader Cal learns a lot about teasing and standing up for others when a weird new student joins his class, while Stella, the tenth-grader who lives with Cal's family to help his mother, practices for her driving test.