Kaoru, a friend from the piano class Ruli once attended, has gone missing. While searching for her, Ruli and the gang find a strange dent and her shoes. And as they continue their search, Hiro is suddenly asked a mysterious riddle.
tobikomu mitaiken no oku no oku ni
Ein Sprung ins Ungewisse,
tiefer und tiefer.
Lanzándose a lo desconocido
Más profundo
Lanzándose a lo desconocido
Más profundo
Pular em direção ao desconhecido, 
cada vez mais fundo
Я погружаюсь всё глубже в неё.