Jason and Midgel set off a series of practical jokes on board the ship, none of which turn out to be very funny to their victims. Then the crew is asked to act as substitute teachers at the Academy. Jason and Midgel help out and see what it's like to be at the wrong end of a practical joke. Cavitus infiltrates the school in an attempt to defeat the Penguins. Naturally everything comes to a head, and Penguins learn a lesson that a joke isn't funny when it hurts somebody.