Ah Dou's full name is Chen Deqing. He was born into a police family and his most admired idol in his heart is Sherlock Holmes. A Dou's father died on duty in his early years and has always been dependent on his mother. Ah Dou has known each other since childhoodPerhaps, Wang Dazhuang, they may also be Ah Dou's only friends. A Dou is accustomed to observing the details of life on the streets, which is why he has developed a unique insight, and his greatest ambition is to writeA detective novel. In order to write novels, A Dou often goes to the library literature room to search for old materials. On this day, A Dou discovered a strange box and a seriously injured person in the literature room, while outside the libraryTwo black clad men broke in. While grabbing boxes with the man in black, Ah Dou miraculously traveled to the Republic of China's Deqing in 1947. Amidst fear and confusion, the modern loser otaku, Ah Dou, had to uniteSheriff Wang of the Republic of China racked his brains to investigate clues and solve cases, embarking on a wonderful journey in his self proclaimed mundane life.