Jôgorô Kobato, who once had a bitter experience due to a deduction activity called "wisdom work", was determined to become a pure and humble citizen. He secretly entered into a "reciprocal relationship" with his classmate Yuki Osanai, who had the same aspirations, and was planning to make his high school debut as a small-time citizen and live a peaceful life. However, for some reason, mysterious incidents and disasters come into their school life one after another. Will they be able to enjoy a peaceful life as small-time citizens?