The family takes a day vacation at the water-park. All except Dewey, who has to stay home with an overage babysitter, which turns out to be more fun than expected. While Malcolm and Reese get into a loop of revenge-pranks, Hal and Lois try to enjoy the day off. As Dewey's babysitter hits the dance-floor, in more than one way, the youngest member of the family sets off on his own. (imdb)