In 2025, Lin Yan, an ordinary high school student in Ning City No. 1 Middle School, picked up a black leather notebook with a lock under the plane tree in the back alley of the school. The cover of the notebook was engraved with a vague pattern of intertwined snakes, and the keyhole glowed with a strange blue light. At this time, he has not realized that this notebook will completely subvert his ordinary life and become involved in a suspense mystery that spans ten years.
