In the early years of the Republic of China, the talented Mr. Qin Yang joined forces with the returned overseas heiress Shen Rou and the quirky young lady Yuan Jingjing. Together, they got to know the detective He Hongfeng, who helped them gradually solve various baffling and mysterious cases throughout the city. They uncovered the sinister conspiracy of the evil Night Deity Society, ultimately protecting the peace of their corner of the world.