Ushio is a freediver with strange powers. He and his friends are at a tropical land in search of a rare fish, the Blue Butterfly. This pursuit leads them to Ayuuru, a local girl who might know where to find the legendary fish.
| Actor | Role |
|---|---|
 Emi ShinoharaSara Kannazuki (voice) | Sara Kannazuki (voice) |
 Nobutoshi CannaUshio Hayama (voice) | Ushio Hayama (voice) |
 Yuri AmanoAyuuru (voice) | Ayuuru (voice) |
 ChafurinGen Kumagai (voice) | Gen Kumagai (voice) |
 Hikaru MidorikawaMuraoka (voice) | Muraoka (voice) |
 Ai OrikasaMadé (voice) | Madé (voice) |
 Masashi SugawaraTatsuya Kannazuki (voice) | Tatsuya Kannazuki (voice) |