While her parents week-end in New York and sister-in-law Lori Beth flies to visit faraway husband Richie, Joanie Cunningham must prove more than her babysitting mettle when she is challenged with both a sick baby nephew and a broken furnace.

Howard Cunningham promises a new car to daughter Joanie if she'll go to the University of Wisconsin instead of UCLA; but his determination turns to dismay when she decides that she doesn't want to go to college...at all!