When a picture of his recently deceased grandfather falls into the ocean, Shima nearly drowns jumping in after it. He is quickly saved by a mysterious man. In a daze, Shima confesses his loneliness to the stranger. Learning the stranger is a merman, Shima takes him home, and names him Isaki. Isaki and Shima quickly become friends, but find out that their feelings for each other might go past those of friendship.