Sixty years ago, a natural disaster drastically changed the human world, causing species to evolve rapidly, and forcing humans to retreat behind walls and barely survive.

Three years ago, her father disappeared and was branded a traitor to humanity. Her sister was forced to live by drinking blood and became an infected person that everyone wanted to kill.

Two young souls struggle to survive in a slum rife with violence and crime.

A lockdown put his younger sister at risk of exposure, forcing Gu Chen to bleed from his hands, and from that moment on, an unexpected accident occurred...

By day, he is the revered "Coroner," an awakened being; by night, she is the "Guardian Angel" who walks in the darkness and hides behind him.

To survive, you have to be ruthless.