Folklorist Lin Mo received a letter from his father who had been missing for seven years. The paper was yellowed and the handwriting was trembling: "The shadow of Heishui Village is not a legend." These nine words led him to an almost isolated village deep in the mountains of southeastern Guizhou - Heishui Village, a place whose name cannot even be found on the map.
The village is shrouded in eternal fog, and the villagers follow ancient taboos that outsiders cannot understand: never go out on a full moon night, never look in the mirror for more than three seconds, and most importantly - never look back to confirm your own shadow. Lin Mo originally thought this was just foolish superstition until he witnessed his neighbor, Old Man Wang, being "swallowed" by his own shadow in full view of the public.
As the investigation deepened, Lin Mo discovered that the research notes left by his father recorded a terrifying pattern: every nineteen years, someone in the village would mysteriously disappear, and all the missing people claimed to "see another themselves" before they died. Under the abandoned ancestral hall in the village, lies the truth of a massacre a hundred years ago; on the walls of the ancestral hall, the same sentence is densely engraved: "It came, it became me."
When Lin Mo finally found his father's final whereabouts, what awaited him was not an answer, but a more terrifying discovery - the shadow that had followed him for thirty years was smiling at him...
