Yumeko Jabami, a second-year transfer student, arrives at Hyakkaou Academy and is introduced around the school by Class President Ryota Suzui. Ryota warns Yumeko that the wealthier students are likely to drag her into a gambling game to take her money. Later that day, Mary Saotome challenges Yumeko to a modified Jankenpon, where the class will drop cards with "rock" "paper" or "scissors" drawn on them, and the two players must win using only the first three cards they draw. After Yumeko appears to be blasted out of the pot, she offers a final bet worth 10 Million Yen ...