It is said that doing Yinmen work can deal with ghosts and gods. There is a popular saying about the "Four Small Yinmen": The executioner's knife hangs on the wall; the coroner's eyes are visible; the paper-making craftsman's craftsmanship is vivid; the second leatherworker's needlework is leather-like. These mysterious industries rooted in the local area are mixed with folk legends and have become strange stories circulated among the people. The series focuses on this mysterious professional group and tells a series of bizarre murders that occurred in Linjia Town in the early years of the Republic of China. A maid died in the City God Temple but her body disappeared; at the scene of the serial murder case, a red-faced paper man was placed next to the body. There are rumors that the paper man killed people... These cases are more strange and weird than one another, and they are all related to the mysterious "Four Small Yinmen". The police had no idea where to start, so they had to ask Shen Xiaohan (played by Peng Yusi), the "second leatherworker" known as the "folk little detective", to come and help solve the case. The gods and ghosts tell strange and absurd stories, and ordinary people solve cases in the mortal world. Is it ghosts or human hearts behind the weirdness? The mysterious truth is about to be revealed.