When photographer Lin Ye opens the eerie package sent by his missing younger sister, a blurry recording of a Nuo opera drags him into a cursed vortex deep in the mountains of western Hunan. A bloodstained, pale-moon costume is wrapped around the case files of an entire opera troupe found hanged twenty years ago. In an old DV recording, his sister's screams mingle with the clang of a gong: "They're beneath the ancestral hall!"
Every Nuo-mask carving above the gates of Qinghe Village has had its eyes gouged out. Just as the midnight ghost opera begins, the bronze mask on the chest of a one-armed Nuo exorcist suddenly flips over, revealing a blood-red Taotie pattern identical to the tattoo on his sister's collarbone. A rainstorm washes twelve new coffins out from beneath the stage. The grooves in their lids bear the imprints of human bodies, yet the village chronicle records that every twenty years, twelve outsiders born under a "yin" sign disappear here.
When the paper cutouts of a mad old woman summon a shadow of his sister, a bronze human-sacrifice vessel in the ancestral hall's cellar reveals a shocking truth: for generations, the Lin family has served as Nuo shamans who guard the "Yin-Yang Pact." Each heir must kill a close relative on the night of the blood moon to complete the sacrifice. His sister, who faked her disappearance to break the curse, now lies on the altar wearing half a Nuo mask. The bloodstained mask in Lin Ye's hand is growing hot. The next blood moon is only seventy-two hours away.
When the Nuo drum sounds for the third time, the living and the dead will exchange fates beneath the two-faced masks. At last, in this death pact that has endured for a thousand years, it is the siblings who must break the red string with their own hands and place the life-taking masks on each other.
