Sumi Renji is Sumi Yoshino’s grandfather and the leader of the “Sumi Group”, the largest yakuza group in the Kansai region. When he arranges his marriage to Miyama Kirishima, Yoshino must move into the ownership of the “Miyama Clan”, the largest yakuza group in the Kanto region. Kirishima warmly welcomes Yoshino, a kind, friendly, and charming young man who no one suspects is a yakuza. This reassures Yoshino, although she initially feels unsafe in this unfamiliar place. But then, a certain event leads Yoshino to see the real Kirishima.