Zhang Weimi, an ordinary social worker, was forcibly dragged into the underworld by a ghost full of grievances on an ordinary overtime night. The ghost claims that he was murdered, but due to insufficient evidence in the underworld and cumbersome procedures in the underworld, it has been difficult to get justice. In order to return to the world as soon as possible and return to his stable life of two points and one line, Zhang Weimi was forced to become an "agent of the underworld", traveling between the world and the underworld to find the truth about the murder for the wronged ghost. As the investigation deepens, he discovers that there are more complex secrets and dangers hidden behind this simple murder.
