As Ako makes preparations for Otokichi's birthday, rejecting the idea of singing for him, she discovers a strange-looking bird, treating its injuries and naming it Pii. As Souta questions Ako about why she doesn't want to sing, Falsetto appears, creating a Negatone from a music box she got from her parents and taking Souta as a hostage. As Ako gathers her resolve to protect her newfound family, the other Cures back her up, and together they are able to rescue Souta and defeat the Negatone. Afterwards, they celebrate Otokichi's birthday where Ako decides to sing for him.