|Katagiri Yuuichi believes friends are the most important thing in the world. Although he is poor, he makes a promise to his four friends that will attend the school trip. The day after the money for the trip is collected, it is stolen! The class suspects his friends, Sawaragi Shiho and Shibe Makoto, and the five are kidnapped the soon afterwards. They wake up in a room, and are told one of them have enrolled them into this "friendship game" where they attempt to clear the debt that was put on them. Who stole the money for the trip? Who enrolled into this game? Will the bonds that Yuuichi and his friends hold, or will they break?