Tsutomu Koshobu is smart enough to have passed his bar exam at the age of 20. He also graduated at the top of the law department at Tokyo University. He had his choice of prestigious job opportunities, but he chose to work at the Fair Trade Commission. The commission is commonly called the Guardian of the Market. There, Tsutomu Koshobu works for the 6th examination team. One day, Kaede Shirokuma joins the 6th examination team. And they team up to tackle difficult cases.