The Abyss Code: the Thirteenth Anonymous Letter

When criminal police captain Gu Shen was investigating a series of bizarre secret room murders, he discovered that all the victims were related to an unsolved case ten years ago. As he gradually got closer to the truth, he discovered that the missing fragments in his memory were closely related to the core of the case. The emergence of the thirteenth anonymous letter not only revealed the true identity of the murderer, but also made him face the past that he did not want to recall. In the choice between justice and humanity, can he break through the layers of lies and find the final redemption?