Yuuichi Katagiri saves up enough money to join his friends on a school trip. But when the gathered money mysteriously goes missing, suspicion falls on two of Yuuichi's friends: Shiho Sawaragi and Makoto Shibe. A few days later, Yuuichi and his friends are tricked to a place to play a "friendship game," a series of games that will test the strength of their bond and trust in each other.