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.

As Yumeko Jabami's fame grows and the reputation of the student council dwindles, Kirari Momobami decides to revolutionize the group. To this end, she announces an election for its next president. The rules are simple: each student in the school receives one chip. Whoever has the most chips by the end of thirty days becomes both the new president and the head of the Momobami clan. Upon receiving news of this development, the Momobami branch families spring into action. Eleven transfer students arrive at Hyakkao Private Academy, each aiming to lead both the school and the Momobami clan. Equipped with unique talents, they will compete to get as many chips as possible—but their chips are not the only things on the line.

Kakushi Gotou is a somewhat popular manga artist whose works are known for inappropriate content. Because of this raunchiness, when his daughter Hime was born, he vowed to keep his profession hidden from her, believing that she will be disillusioned if she finds out. This paranoia-induced belief leads Kakushi into hectic situations. Despite being a single father, he does his best and often resorts to extreme ends just to protect his secret, such as guising as a salaryman every day or holding emergency drills in case Hime somehow finds her way to his workplace. Kakushigoto tells the story of a father and daughter living side by side, maintaining their peaceful existence as the father attempts to preserve the status quo. However, there is a saying: there are no secrets that time cannot reveal. In time, Hime must learn the reality behind the things she took for granted as she grew up.

Unlike many schools, attending Hyakkaou Private Academy prepares students for their time in the real world. Since many of the students are the children of the richest people in the world, the academy has its quirks that separate it from all the others. By day, it is a normal school, educating its pupils in history, languages, and the like. But at night, it turns into a gambling den, educating them in the art of dealing with money and manipulating people. Money is power; those who come out on top in the games stand at the top of the school. Yumeko Jabami, a seemingly naive and beautiful transfer student, is ready to try her hand at Hyakkaou's special curriculum. Unlike the rest, she doesn't play to win, but for the thrill of the gamble, and her borderline insane way of gambling might just bring too many new cards to the table.