The world's richest man, Koichi Mikage, has been hiding his identity and raising his son while working as a convenience store cashier. But his son marries Yuki Hanyu, the bride of the arrogant Hanyu family. Surrounded by an intimidating fiancée, mother-in-law, and sister-in-law, his son Kazuma Mikage is always forced into a passive position. He didn't want his father Koichi to attend the wedding, but Koichi absolutely refused to give up attending. At the wedding, Kazuma is mercilessly bullied, and Koichi stands up for his son. Despite facing ridicule, he offers a huge congratulatory gift, but when his drink is tampered with by malicious relatives and his late wife is insulted, he reaches his limit. Just then, the powerful adopted daughter he once raised suddenly opens the door and appears, declaring that she wants to become the Mikage family's bride, shocking the entire venue.