Despite Stan's objections, Francine buys Steve the dog he's always wanted. However, when the dog suffers a horrific accident, Stan refuses to take the pup off life support because of a traumatic childhood incident.

Stan discovers that Francine was unfaithful one night before she and Stan married. With the possibility that Hayley may not be his biological daughter, he travels back in time to find out who the mystery dad might be. But when he inadvertently disrupts the events of the past, he must do everything to avoid changing the future.