When Lisa discovers a talent for solving crossword puzzles, she enters a crossword tournament… unaware that Homer is betting against her.

Bart and Lisa sit outside the house selling lemonade. Unfortunately, there are no takers. Their luck changes when Cletus and his large family stop in front of the house. Homer tries to push his way to the head of the line, but Bart tells him it’s “cash only.” Homer heads to Moe’s tavern. There Mrs. Krabappel offers to buy Homer a beer if he’ll act as her proxy and break up with Skinner for her. Homer does such a good job that Lenny asks him to dump his girlfriend, Doreen. A part-time field agent for the Springfield Department of Commerce tells Lisa and Bart they’ll need a permit to continue selling lemonade. Reluctantly, Lisa and Bart make their way to the License Bureau, where they’re forced to wait in line with a group of disgruntled townspeople. The source of the delay is the license clerk, who’s struggling with a crossword puzzle. Lisa offers her help, and within a short period of time, completes the puzzle. Lisa discovers that she’s a cruciverbalist: a fan of crossword puzzles. Homer makes his way to a gay dance club, where he helps Grady (from the episode “Three Gays of the Condo”) to break-up with his significant other, Julio.

Homer turns his talent into a business: the Sweet Conclusions Break-Up Service. It’s an instant success. At school, Chalmers and Skinner discover Lisa’s talent for solving crossword puzzles, and interest her in enrolling in a citywide crossword tournament. Marge worries that Homer is making it too easy for couples who’ve hit a rough patch in their relationship to break up. Shortly thereafter, Homer dreams about the spirits of relationships he’s ended. When he wakes up, Homer decides it’s time to get out of the break-up business. Homer accompanies Lisa to the citywide crossword tournament. As the competition gets underway, Homer hangs out in the hotel bar, where he bets money on the outcome of the competition. Lisa wins match after match. Elated, she tells Homer she might win the competition. She fears she might sabotage herself just when she’s on the verge of happiness. Homer has wagered a lot of money on the outcome. When he hears Lisa’s self-doubts, he changes his mind, and bets against her. The final crossword match is between Lisa and Gil. Gil hustles Lisa, and wins the competition. Homer cheers when he hears the news.

Flush with cash, Homer takes Marge to dinner at a swanky restaurant. During the meal Homer admits that he bet against Lisa. Marge urges Homer to keep the information a secret, as Lisa will be heartbroken. When Lisa notices that Homer bought new shoelaces, highlighted his hair, and had his car antenna straightened, she grows suspicious. Eventually Homer admits that he bet against her in the tournament. An eerily calm Lisa tells Homer she’s not mad at him. Homer suspects otherwise. Homer approaches Lisa at school, a gift-wrapped present in hand. Lisa suddenly erupts in anger. She tells Homer that he stopped being her father when he bet against her. She says she’s now calling herself “Lisa Bouvier.” A horrified Homer makes his way to Moe’s bar, and tells the barflies about his troubles. Moe urges Homer to win his daughter back. Later, Lisa loses herself in a New York Times crossword puzzle. While filling it out, she realizes there’s a secret message in a diagonal row of letters. The message reads, “Dumb Dad Sorry For His Bet.” Lisa approaches Homer, who admits to contacting The New York Times crossword editor Will Shortz and master puzzle constructor Merl Reagle, who created the special puzzle just for Lisa. Shortz tells Lisa she read only part of the message. He tells Lisa to look at the first letters of all the clues. It turns out to be a heartfelt message from Homer. Lisa is touched. She hugs her father.