The bizarre murder case of "missing heart" intersects with the cold-faced forensic doctor Shen Xiuyan, who is known as the "human truth machine". Shen Xiuyan has special demon-breaking blood and can detect aliens. He focuses on Jiang Li, who looks weak but is actually extremely powerful in combat. From testing and doubting each other, the two were forced to form a team to fight against the evil spirits hidden in the shadow of modern cities. As the truth emerges, Jiang Li discovers that Shen Xiuyan is actually the reincarnation of the person she has been looking for for thousands of years, and Shen Xiuyan also falls in love with this dangerous and charming "non-human" while risking his life to protect him again and again.
