IO

Taiyo Nakabiru travels to Okinawa hoping to meet beautiful girls and go diving. When he tries to approach a girl, she tells him he killed her mother, though Taiyo has no memory of ever visiting the island. She and her two sisters, Nagisa, Shibuki, and Mio Miyara, all seem to know him. Taiyo persuades the sisters to let him help with their work and teach him to dive. As he spends time with them, memories of his childhood with the three sisters begin to return, while strange events connected to a mystical white whale start to haunt them.