IO

Taiyo Nakabiru travels to Okinawa, seeking adventure and romantic connections. However, his initial encounter with a local girl takes an unexpected turn when she reveals that he is responsible for her mother's death, a claim that is echoed by her two sisters, Nagisa, Shibuki, and Mio Miyara. Despite his initial denial of any recollection of visiting the island, Taiyo convinces the sisters to let him assist them with their work and learn diving techniques from them. As he becomes immersed in their lives, fragments of his childhood begin to resurface, and a mysterious connection to a mystical white whale starts to unfold, intertwining their fates.