Despite having a lot of Notes, Mephisto finds he needs more to complete the Melody of Sorrow. As Hibiki and the others ask the Crescendo Tone what Muse's motives are, she tells them to think about what a Pretty Cure fights for, with Otokichi telling Dodory something similar. Mephisto creates a Piper Negatone to lure in other Notes and make it stronger, leaving Muse conflicted over what she should do. As the Pretty Cure fight the Negatone, Eren notices the headphones on Mephisto were the same used to brainwash her, leading them to the conclusion that someone above Mephisto is brainwashing him. Though the Pretty Cure defeat the Negatone, Mephisto uses the Notes to power himself. Acknowledging the girl's desire to free Mephisto from his evil heart, Muse unmasks herself, revealing herself to be Ako, who is actually Mephisto's daughter. As Ako tries to plea to Mephisto to return to normal, the evil noise proves too much and he is forced to retreat.
ミューズの守りたいもの。それはメフィストだった。ミューズがメフィストをかばったことでその事実が発覚する。ミューズとも戦わなければいけない、プリキュア同士で戦うことを響は否定するが...。
