The year is 1977, in Kabukicho, Shinjuku. Shoichi Sakurai, a professional underground mahjong player, has come to be known as the "Juku Mahjong Demon." One day, he is asked to play mahjong on behalf of a yakuza boss who is looking after him. However, the person he is playing against turns out to be a big shot known as the "Emperor of Ginza."