The town of Kanon overflows with music. There lives Houjou Hibiki and Minamino Kanade, two childhood friends. However, when they became middle-schoolers, for some reason they would argue with each other every time they meet.
One day, a fairy called Hummy from Majorland appears before them. Hummy requests that Hibiki and Kanade transform into Precure to protect the world from Mephisto, King of Evil in Minor Land. There is a legendary score, within which is written the "Melody of Fortune" and Mephisto plots to rewrite it into the "Melody of Misfortune".
Although Hibiki and Kanade are usually unable to see eye to eye on anything, in this matter their hearts are one, and a new Precure legend is born!