Set in 1920s, Tianjin city. It tells the incredible secret behind a series of dubious cases in Tianjin police department.Set in 1920s, Tianjin city. It tells the incredible secret behind a series of dubious cases in Tianjin police department.Set in 1920s, Tianjin city. It tells the incredible secret behind a series of dubious cases in Tianjin police department.