Thornton Melon (Rodney Dangerfield) is concerned that his son Jason (Keith Gordon) is unsure whether to go to college, so the uneducated self-made millionaire encourages him by signing up as a student as well. As Jason tries to establish himself among his peers and make the diving team, Thornton falls for a pretty professor (Sally Kellerman) and gets others do his schoolwork for him. When the suspicious dean (Paxton Whitehead) finds out, Thornton needs to show he can get by on his own.
Feeling forgotten by the children of the world, old St. Nick decides to skip his gift-giving journey and take a vacation. Mrs. Claus and two spunky little elves, Jingle and Jangle, set out to see to where all the season's cheer has disappeared. Aided by a magical snowfall, they reawaken the spirit of Christmas in children's hearts and put Santa back in action.
Bill, Jeff and Judy begin building rafts to help the human tribes reach New Valley; while going through a nearby jungle, the trio encounters a very unlikely sight: a wrecked U.S. spaceship and its pilot, Ron Brent.
A terrifying force from Outer Space brings freezing death to the personnel of Moonbase Alpha. One man has been chosen as the instrument of destruction.