Yoshimoto Koya becomes a tutor to a student, Numata Shigeyuki, an underachiever on the verge of dropping out of middle school. Expecting immediate results, Shigeyuki’s father makes a deal with Koya that if he could make Shigeyuki return to school within a week, he would receive a 100,000 yen bonus. Koya accepts the offer, replying that he would only need 5 days to complete the mission but demands that no one should interfere with his methodology in doing so.