Kyuta Yamada, a once-devoted family man, faces financial turmoil after devastating stock market losses strain his marriage and household stability. His children exhibit a volatile sibling dynamic marked by physical altercations and relentless teasing. A demonic incursion, triggered by a summoning ritual, invades the home, irrevocably altering family relationships. The entities entice each member with tailored temptations: Kyuta amasses sudden wealth, financing a five-member harem, while his spouse forms a bond with the demon Ophisto Bazooka. Their daughter pursues sadomasochistic encounters with Mephist Dance, a demonic partner. Though initially resisting, the family gradually succumbs to the hedonistic allure of their new existences. Kyuta abandons efforts to mend familial bonds, instead immersing himself in transactional indulgences. The household fractures irreparably as he permanently sheds his former identity as a traditional patriarch, embracing a life defined by excess and supernatural bargains.