When Aoki Soubi journeys to his late mother's island, he encounters Tenyuu, the harbinger of a startling revelation: only males reside on the island. Tenyuu, aware of Aoki's true heritage, abducts him, unveiling a legacy that rests solely on Aoki's ability to conceive daughters. Subsequently, Tenyuu, alongside his siblings Yuki and Kaitou, become romantically entwined with Aoki, each harboring a fervent desire to father his offspring.