Hyakkaou Private Academy is a prestigious institution for the privileged, which was first established 122 years ago. The students there are ranked by their gambling winnings. The winners receive everything including fame and fortune. The winners also dominates the losers. One day, female transfer student Yumeko Jabami arrives at Hyakkaou Private Academy. Yumeko Jabami has a pretty appearance, but she is a gambling maniac who loves high stakes.