Marion wants to join a dance contest but Howard and the kids think it's ridiculous. But she decides to enter with Fonzie and they spend their free time practicing. When she acts strangely because she's keeping it a secret from everybody, Howard wonders what's going on. And when Arnold who knows about it let's it slip that Marion is seeing someone else, Howard follows her. And when he sees her with Fonzie he loses it.
In a sneaky scheme to widen their dating pool, Richie, Potsie and Ralph stage a bogus beauty contest, planning to rig the vote to insure that a ringer provided by the Fonz will win but won't accept the promised fabulous prizes the boys can't afford and never intend to award.
Fonzie's former girlfriend and fellow motorcyclist, Pinky Tuscadero comes back into his life, making him realize he still loves her. She wants to be in a demolition derby with him but Fonzie states that it's no place for a woman.
After being injured in the head at the derby from "The Millachi Crunch". Pinky is hospitalized. Fonzie gets revenge with the brothers and wins the derby, he also realizes that he wants to be more than just Pinky's boyfriend.
Richie's plans to party while his parents are out of town are ruined when Fonzie invites the very pregnant wife of one of his oldest friends to stay in Joanie's room and orders Richie to keep an eye on her until her husband returns from a road trip.
Richie's secret scheme to convince sophisticated Cindy Kendall that he has his own apartment by exchanging bedrooms with Fonzie is foiled when her furious father comes looking for her in the middle of the night.