Kimihito Kurusu enjoyed a peaceful, dull life alone while his parents were gone, until the monster chicks began to arrive! This alternative reality represents modern Japan, the first country to encourage non-human species absorption into civilization. Because to the incompetence of interspecies exchange organizer Agent Smith, who installs Kimihito as the homestay guardian of a Lamia named Miia, the newly-minted "Darling" rapidly attracts females of all breeds, culminating in an ever-growing harem flush with sensuality and desire.