In the Republic of China period, there was an active police inspector in the Shanghai Police Department. His name is Wu Shiguang. He is a fat man with a huge body, humorous and considerate. He, together with his colleague Cui Youhe and assistant Dong Shaojie, formed a detective team, uphold justice, get rid of evil and support the good, solved many major cases and became a great detective who shocked the Shanghai at that time.