Yoko Yuki is a genius female gambler born with a keen sense of luck. She has a winning streak at all kinds of gambling, including horse racing, boat racing, and roulette. This is because she inherited the blood of her mother, a female gambling expert. One day, Yoko is introduced to a roulette club, where she meets Ichimatsu Rikio, a notorious land grabber, and is challenged to a one-on-one challenge