When the family goes to a water park for a day, Dewey is left home with an elderly, stern babysitter. Francis is hustled at pocket billiards by his military-school commandant.

After Hal forbids Dewey from inviting his peculiar classmate Chad over for a sleepover, Dewey quickly finds out that his father had good reason to warm him. Meanwhile, Malcolm and Reese find out that they are not as popular as they once thought, then plot "revenge" on their classmates.