The Minor Trio learn about the Healing Chest and decide to investigate. Meanwhile, as Hibiki becomes downhearted after failing an English exam, mysterious musical incidents begin to occur around her. Just then, the Minor Trio create a Negatone from Hibiki's exam paper, which puts the Cures into an English test, attacking Hibiki for every question she gets wrong. The Cures do manage to defeat the Negatone.