Taiyo Nakabiru ventured to Okinawa in pursuit of alluring women and an opportunity to go diving. However, his amorous advances towards a certain woman resulted in her blaming him for her mother's demise. Though Taiyo had no memories of ever being in Okinawa, the woman and her siblings recognized him. Despite initial skepticism, Taiyo managed to persuade Nagisa, Shibuki, and Mio Miyara to allow him to assist them with their endeavors and receive diving lessons. While spending time with the sisters, Taiyo gradually recollected his childhood experiences with them. Nevertheless, strange and enigmatic occurrences began taking place, including a mystical white whale that terrorized them.
