Year 201X. Japan has achieved economic revitalization due to the legalization of betting authorized by the government due to the enforcement of the betting regulations. A gambling vocational school (commonly known as Tobasen) was established to train specialists so that they can compete with other countries even in gambling. Only the gambling arm can climb. Meanwhile, Mizuho and four female students are gathered in the classroom. They were some of the most problematic children in Tobasen. Then, the teacher tells me the startling test contents. If he wins, he will graduate as a gambling specialist. However, if he lost, he was stripped of all his clothes, and he was a mahjong undressing, breaking the rules that death sanctions were waiting.