In the Second OVA of the Kono Dan series, Shima impulsively dives into deep waters to retrieve a photo of his late grandfather, only to be rescued by a peculiar stranger who is human above the waist and merman below. This unexpected encounter sparks a unique bond between Shima, who has always felt out of place, and Isaki. Despite their growing connection, navigating a relationship between two individuals of such different species proves to be a challenging and unconventional journey, testing the boundaries of love and acceptance.