The Kirishima family is an old family connected to a regional financial conglomerate. Kirishima Kazuki, the heir to this prestigious family, inherited the family assets after the sudden death of his older brother, Mizuki. With both parents already deceased, Kazuki became the last surviving member of the Kirishima family. Kazuki is grief-stricken after losing his brother, with whom he had a very close relationship. Izumi Kaoru, a young butler-in-training, is staying by his side. The Izumi family has served as Kirishima's butlers for generations, and Kazuki places great trust in them. Kazuki's first task as the head of the family is to perform the "Funauchi" funeral ceremony, a tradition passed down through generations of the Kirishima family, for 49 days without fail. In a villa nestled deep in the mountains on the border of the prefecture, built on the land of the Kirishima family, he spends his days performing the ritual to honor Mizuki's soul. But those peaceful days are suddenly shattered when one day intruders appear. Mimasaka Shousuke, Tachibana Yuuya, Yukinomiya Tooru, and Mizusawa Hirotsugu. All of them are sons of Japan's most prominent families. Belonging to the ultra-upper class and unsatisfied with ordinary forms of entertainment, they come up with the idea of ​​"using" Kazuki in a "game" to relieve their boredom. Kazuki, who has never even experienced love, let alone sex, is tormented by an unspeakable nightmare. He suffers every day, troubled by the unreasonable "game". Furthermore, strange phenomena begin to occur at the mansion. A gruesome carcass of a small bird is discovered in the forest on the grounds. Every night, Kazuki is haunted by mysterious nightmares. The story unfolds as the unfair "game" orchestrated by the intruders intertwine with the "secrets" surrounding the Kirishima family.