Internet novelist Lu Xiaoyu happened to meet Jiang Tiantian, a criminal policeman who had just been transferred to the town, and accidentally formed the "Fat Man Detective Bureau". In the seemingly peaceful town, bizarre cases occurred one after another: missing goldfish, ghosts in the night, mysterious disappearances, treasure mysteries in ancient houses... The members of the Detective Bureau showed their talents, and uncovered the truth layer by layer in the midst of comedy and tension. Inadvertently, the protagonists discovered that there seemed to be hidden clues in all the cases - an old disappearance case twenty years ago connected everyone's fate. As the mystery is solved, the protagonists gradually grow up, face their own dilemmas, and write a mystery legend with ups and downs, joy, humor, and warmth.