When Homer and Marge's sex life fizzles out, Grandpa whips up a batch of bottled passion for Homer. The home remedy proves an amazing success and after a marathon snuggle session with Marge, Homer convinces his father to try and sell the potion. Hitting the open road, Homer and Grandpa rake in the bucks and bond like they have never before. But when they find themselves driving by the house where Homer grew up, the old resentment and hostility bubbles up between them. After much fighting and many angry proclamations, Homer and Grandpa make up.