The story is set in the private Hyakkao Academy, which is celebrating its 122nd anniversary. This is a prestigious school with tradition and status, attended by the children of bigwigs in the financial world. The students' class is determined by their gambling skills. The winners gain status and reputation, while the losers are deprived of their property and dignity. The story begins with the appearance of the mysterious transfer student Yumeko Jabami (Minami Hamabe). Yumeko is usually elegant and quiet, but once she starts gambling, she becomes a "crazy gambling witch". She uses her extraordinary insight, memory and negotiation skills to play with her opponents, and she will fight to the death even at great risk, and finally push them into the abyss of destruction.