That summer, Hu Buyu's "accident" drowning in the river became a thorn in the side of his sister Li Lu's heart. A black notebook scattered with fragmentary dates reveals the lie behind the death of his sister - is the class teacher Dai Yue mentioned repeatedly in the diary a gentle teacher, or a devil in human skin?
Li Lu sneaked into the Sunshine Community as a neighbor and approached Dai Yue step by step, but unexpectedly uncovered the campus undercurrent: the despicable behavior of his sister's boyfriend, the well-kept secrets among his classmates, and the cold murderous intention hidden under Dai Yue's smile. When the truth about the revenge in the dormitory and the tampering of the diary emerged one by one, Li Lu was shocked to realize that everyone was a chess piece in the game.
And there is a deeper nightmare locked in Dai Yue's cabinet - the blood debt ten years ago, the forbearance and dormancy of youth, finally turned into a revengeful blade this summer.
Lies and truth intersect, and the boundaries between good and evil collapse. When the police knocked on the door, Li Lu held the blood-stained diary tightly and suddenly understood: No one in this muddy water is innocent.
Purpose: Deep in the mud, there are always people who are willing to be lantern bearers and burn out the last ray of light for the truth.