After a dispute with his friend Senichi Aoyama, high school student Yasuto Akashi decided to skip class. But upon his return, he discovered the school was locked up. To his horror, he witnessed a giant cat head burst through a window, with Aoyama dressed as a rat and covered in blood. That day, only three students managed to survive, and similar incidents occurred around the world. Akashi's peace was short-lived, as he was chosen to participate in a deadly game for those who missed school on that fateful day.
