In the back mountain of Xuanzong of the Qing Dynasty, there was a lame black cat with deformed bones. Every full moon night, it would cry like a baby. Ali, a new medicine boy, unexpectedly discovers that this cat can speak human words. On a rainy night, he witnesses its bones twist and swell, transforming into a young man in green clothes stained with blood. It turns out that this is a nine-life cat demon whose bones and muscles were ripped out a hundred years ago. Because the demon pill is sealed in the center of the mountain-protecting formation, every rainy day has to endure the pain of bone reorganization and heart-cutting.
When cracks appeared in the mountain-protecting formation and the leader died suddenly, Ali found three black iron nails embedded with talismans on the cat demon's spine. Are those dark shadows lingering in the back mountains at midnight, traitors who want to silence themselves, or body-snatchers who covet the cat demon's bloodline? And every time the cat demon transforms into a twisted spine, a ninth demon bone glowing with golden light is slowly growing...
Intention: Destiny is like a lock, and love is the only key - when the gods regard the common people as puppets, mortals can also tear apart the book of fate and temper the light of god-killing humanity in the blood and bones of seven generations.