The Simpsons Season 20 Episode 5

Taking the kids for a holiday at the Kozy Kabin,the Simpsons pick up a young couple hitching,and recall two past incidents involving stays at the Kabin. Twenty years earlier they accepted a lift from the newly-wed Maude and Ned Flanders,determined to stop them from having pre-marital sex. Five years later each turned up at the Kabin on the rebound with a sexy partner who,as a result of the meeting,got married themselves. Now it's Bart and Lisa who act like a bickering couple though it inadvertently saves their parents' lives.