Children from influential families in politics and businesses attend the Hyakkaou Private Academy. There, the hierarchy of the students are classified by a series of games. Students that win the games are on the ruling side and the students who lose become slaves. One day, a mysterious girl, Yumeko Jabami (Minami Hamabe), is transferred to Hyakkaou Private Academy. She looks pure and pretty, but she is actually a compulsive gambler and seeks out the thrill of taking calculated risks.
Hyakkaou Private Academy. An institution for the privileged with a very peculiar curriculum. You see, when you're the sons and daughters of the wealthiest of the wealthy, it's not athletic prowess or book smarts that keep you ahead. It's reading your opponent, the art of the deal. What better way to hone those skills than with a rigorous curriculum of gambling? At Hyakkaou Private Academy, the winners live like kings, and the losers are put through the wringer. But when Yumeko Jabami enrols, she's gonna teach these kids what a high roller really looks like!
High school student Aya Tsukimori becomes cursed and is unable to leave her school dormitory. Meanwhile, many students begin reporting ghost sightings at the school, while others go missing and are later discovered to have drowned mysteriously. Soon, Aya attempts to communicate with fellow student Michi Kazato, who begins investigating the disappearances of her friends.
