One day, Yukari (ゆかり) went to the sea with her husband and drank at a bar, then lost consciousness. How long had she slept? When Yukari woke up, an unfamiliar man in black was standing there. It turned out that her husband, who had taken on a large debt, had handed Yukari over to a criminal organization as payment. The place she was taken to was the underground of a port warehouse, where an illegal gambling event called the "闘尻会" (Butt-Fighting Association) was held; there she found Naho (奈穂) and Mari (まり), who live as pawns in the bets, and they said, "From tomorrow, hell will begin."
