After his parents' divorce, Shima Kawauchi was welcomed by a compassionate grandfather. When the elder died, Shima found himself utterly alone. Overwhelmed with sorrow, he wept beside the sea at night; a slip sent him plunging into the waves. Unable to swim, he nearly drowned until an exceptionally handsome merman rescued him. Observing Shima's distress, the mermaid—whom he christened Isaki—urged him to keep her until she fully healed. As they settled together, a connection blossomed that crossed species and gender boundaries. Their shared nights by the moonlit tide deepened their companionship, forging a promise that neither nor distance could unravel.
