Qinglan Town, a remote town surrounded by rolling green mountains, is shrouded in thick fog all year round, and there are strange legends about the "Full Moon Blood Sacrifice". Lin Mo, a former criminal policeman, came here to work as a forest guard to escape the trauma of his past. However, he encountered a mysterious deceased person on a rainy night - a red rope dagger stuck in his back, half a jade pendant engraved with the word "Lan" tightly clutched in his hand, and a strange note left behind before his death: "Qinglan Mountain, full moon night, blood sacrifice begins, old friend returns."
The body of the deceased disappeared mysteriously, Mr. Chen's family heirlooms were stolen, and the townspeople kept secrets about the past... A series of strange things happened one after another, and Lin Mo was forced to be involved in the investigation. In the process, he met Su Qing, a female doctor who was looking for her missing parents. The two discovered that the deceased's jade pendant, the legend of the blood sacrifice, and the Chen family's secrets were vaguely connected to the disappearance of Su Qing's parents ten years ago and the death of Lin Mo's partner three years ago.
As the night of the full moon approaches, the fog in Qinglan Town gradually lifts: It turns out that there is a secret organization hidden in the town that has lasted for hundreds of years. The "blood sacrifice" is not a superstitious legend, but to suppress (or awaken) a certain sealed existence; Lin Mo's partner, Su Qing's parents, were all silenced for touching the truth; and Lin Mo himself has an innate connection with the "token" of Qinglan Town.
In the struggle between protection and revelation, survival and truth, Lin Mo and Su Qing must break the centuries-old curse and find out the mastermind before the last full moon night, not only to comfort the deceased, but also to prevent Qinglan Town from completely falling into the abyss...
