Delivery boy Chen Mo received a strange order on a rainy night and accidentally got involved in the incident of a bronze door that can connect ancient and modern times. This palm-sized bronze door not only hides secrets that span thousands of years, but is also closely related to the bloodline of the "gatekeeper" hidden in him - whenever the bronze door is opened, he can always see fragments of figures in ancient costumes in his dreams. In reality, graffiti on unfinished buildings, mysterious text messages, and the constant emergence of mini bronze doors are all pushing him into a game of life and death.
As the investigation deepened, Chen Mo discovered that behind the bronze door was a "mirror dynasty" on the verge of collapse. The people there feed on the "obsession" of modern people, and his mission is to find a way to seal the door before it is completely opened. In the process, he got acquainted with Su Qingyuan, a history girl who can read ancient texts (seemingly cold but actually carrying a family mission), and Lao Jiu, a mysterious antique shop owner (who appears to be a philistine but always helps at critical moments). When the three of them pursue the truth, they not only have to fight against the "shadow servants" of the mirror dynasty, but also uncover the blood and tears of the Chen Mo family's past of guarding the bronze door for generations...
