Mary's sister comes back into her life and Dick comes up with a sneaky plan to help Mary get even with her. Meanwhile Sally and Harry open a youth center in the living room.

Dick and Mary double date with Don and Sally leaving everyone feeling a little insecure. Meanwhile Mary and Don run into each other in a food store and, consumed by what they'd heard about each other in bed, share a kiss. Elsewhere, Harry and Tommy follow in the footsteps of Jack Kerouac and take to the open road.