When Fang Xu, a postgraduate entrance examination student, stayed up late reviewing in the library, he accidentally triggered the "knowledge cage" and was trapped in the strange space of the library. Under the threat of a 72-hour countdown, he and Su Wan, who was also trapped, solved the puzzle and gradually discovered the truth: it was their respective fathers who framed Lin Yan. Lin Yan was psychologically distorted because of being framed, so he created a prison and used the life of a graduate student to take revenge on his "framer". Fang Xu and Su Wan must find Lin Yan before the countdown ends, uncover the truth about that year, and give Lin Yan justice. The "blood debt mark" that appeared inexplicably on Fang Xu's wrist hinted at an unknown connection between him and Lin Yan. In the process of searching for the truth, Fang Xu gradually awakens the "spiritual ability", which can affect reality through emotions, but every time it is used, it consumes mental energy. Can they solve the mystery, reveal the truth, and rescue the trapped classmates within 72 hours, while avoiding becoming the next victim of the "Blood Debt Seal"?
