Her name is Mary Saotome—she is brazen, insolent, and defiant, yet highly intelligent. Upon transferring to Hyakkaou Private Academy, where a student's worth is determined by their wits through gambling, she seizes a glorious win against a classmate and immediately captures the attention of the devious student council members.

With the bottom of Hyakkaou's rigorous hierarchy determined by least gambling winnings, the future for Tsuzura Hanatemari looks grim. As Tsuzura's childhood friend, Mary resolves to rise through the ranks and secure enough money to free Tsuzura from the shackles of the unjust system. Mary's perseverance and refusal to lose drive her to surpass and humiliate even the strongest opponents, but certain student council members seem to have greater plans for her.