Steve Urkel is still the annoying neighbor to the Winslow family, getting into situations such as bringing a lab chimpanzee to their home, suing Carl for destroying his priceless stick bug, creating a robot that chases after Laura, and joining the church choir despite being tone-deaf.
It's a battle of brains vs. brawn, as Steve and a braggart classmate vie for the affections of Laura in a rope-climbing contest.
Laura suggests that Steve uses his brains to win the competition, leading him to invent a jet-pack to do so.
Meanwhile, Carl and Eddie try to fix a leak in their roof, against Harriette's advice to call a professional.
Though they succeed, Carl ends up falling off the roof and breaks both his arm and leg.