Marge fears that Homer will embarrass her at the annual Springfield Chili Cook-Off. She reminds him that his behavior the previous year, when he consumed too much beer and frolicked nude inside a cotton candy machine. Homer promises to behave. Sampling this year's various chilis, he dismisses them as bland and timid. However, when he eats a dish laces with potent Guatemalan peppers, he begins to hallucinate.

In his altered mind-state, Homer experiences a fantasy involving a pyramid and a mystical coyote. The coyote tells him that in order to become a complete person, Homer must find his soul mate. When Homer arrives home from the cook-off, disoriented, Marge accuses him of breaking his promise.

Concerned that Marge is not really his soul mate, Homer leaves the house and roams the city. He notices a lighthouse in the distance and convinces himself that only the lighthouse keeper, "the lonliest man in the world," will understand him. Once inside to structure, however, Homer finds that the lighthouse is directed by an automatic computer system. Marge arrives at the lighthouse and apologizes to Homer for accusing him of getting drunk. Homer realizes that Marge is his soul mate after all.