There is an unwritten rule in Yuncheng City——
On the 13th of every month, strange cases will occur in the jurisdiction.
The surveillance screen goes black, witnesses lie, and evidence disappears. In the end, the case can only be closed as an unsolved case.
Old detective Lu Zheng never believes in evil.
Until he inherited his father's legacy - a black notebook numbered "13" that can never be opened.
From then on, every day on the 13th, he could see things that others could not see:
The residual images of the crime scene, the last sight of the deceased before his death, and... Those who should not exist.
"Dad, what exactly did you discover back then?"
When he finally found out the truth about his father's sacrifice, he discovered——
Some files cannot be read.
Some rules cannot be broken.
Some people should never be forgotten from the beginning.
