It is revealed that Ako is also Aphrodite's daughter, Otokichi's granddaughter and the princess of Major Land. Ako explains how Mephisto once entered the Dark Forest to search for the Healing Chest, but came out evil. When she learned about Mephisto stealing the Legendary Score, she gained the power to become Cure Muse and took on her masked identity. Meanwhile, as Mephisto tries to remember his past, the evil noise takes control of him again and he comes to the human world again to face the Pretty Cure. As Mephisto's evil power proves too much for Hibiki, Kanade and Ellen, Aphrodite appears before him, encouraging Ako to transform and join the fight. Ako is reluctant to fight, but the other Cures convince her to fight to return Mephisto's heart to normal. She lands a resounding hit to his heart, which helps him realise who he is and returns him to his normal self. As the Minor Trio takes charge of completing the Melody of Sorrow, it is revealed the name of their true enemy is Noise.
アコがキュアミューズの正体だった。そして、メフィストがアコのパパだという。昔のパパは優しかったと、彼女は話す。なぜ優しかったはずの彼女のパパがあんな風になってしまったのか、その理由が明らかになる。