The Simpsons (1989): Season 20, Episode 6

20 - 6: Homer and Lisa Exchange Cross Words

Lisa discovers her amazing talent for doing crossword puzzles and becomes an expert cruciverbalist, and she soon enters a citywide crossword puzzle tournament. Homer, short on cash after abandoning his "Sweet Conclusions" professional break-up artist business, goes to cheer Lisa on at her tournament and discovers an underground crossword puzzle betting ring. In the ultimate betrayal, Homer profits from betting against Lisa in the championship match. When the heartbroken Lisa finds out, Homer must spell out his love for her with a little help from New York Times crossword puzzle editor Will Shortz (guest voice as himself) and master crossword constructor Merl Reagle (guest voice as himself).