Riginetta, a high-spec robot girl, seeks a relaxing getaway on a cheap desert island, only to discover it is a "stigmatized property" overrun by monsters. After battling slimes and meeting a friendly Lamia, she learns that the island's inhabitants were once humans transformed by a mysterious royal ritual. Despite the monsters' suggestive advances, Riginetta is encouraged to venture deeper into the ancient ruins to uncover the source of the island's curse.
Riginetta enters a portal leading to the Demon Realm to uncover the cause of the island's monster infestation. Along her journey, she is repeatedly overwhelmed by the erotic attacks of a hypnotic Gazer and a seductive succubus before facing the powerful Queen of Darkness. After a climactic battle of mana depletion and strange transformations, Riginetta is shocked to find the monsters welcoming her as their new resident and leader.