In Toronto, 22-year-old Scott Pilgrim is a bass guitar in Sex Bob-omb, a floundering garage band. To the disapproval of his friends and younger sister Stacey Pilgrim, he is dating Knives Chau, a 17-year-old high-school student. Scott meets an American Amazon (company) delivery girl, Ramona Flowers, having first seen her in a dream, and loses interest in Knives, but doesn't break up with her before pursuing Ramona. When Sex Bob-Omb plays in a battle of the bands sponsored by record executive G-Man Graves, Scott is attacked by Ramona's ex-boyfriend Matthew Patel. Scott defeats Patel and learns that, in order to date Ramona, he must defeat the remaining six evil exes.