Antoine is a lawyer living in New York. On his way back to France for the final round of a job interview, Antoine finds himself sitting right next to his ex-girlfriend Julie. With a seven-hour flight ahead of them, they are going to have to speak to each other.

Betty Blue, a mentally unbalanced and sexually aggressive free spirit who becomes involved with Zorg, a repairman moonlighting as a writer. The two engage in a variety of sexual encounters, and grow more passionate toward each other. Betty finds Zorg’s book and is aggressively supportive; over time, her instability begin to catch up with her, leading to a grisly and shocking conclusion.