Twenty years ago, the mysterious and brutal Cape Tongyi created a serial murder case that shocked the country. Although South Korea dispatched a large number of police forces to launch an overwhelming search, the murderer has never been able to be arrested. The ghostly Cape Tongyi has left unhealed scars in the hearts of countless people. River Wunian (Yin Sang-hyun), the chief of the serious crime unit of the Nippon Coal Police Station, was rudely investigated as a suspect. He vowed to catch the Cape Tongyi himself with hatred. At the same time, Yang Tiekun (Sung Dong-ri), the police officer in charge of the case, gave up the opportunity to be promoted and took the initiative to request a transfer to Nippon Coal, but he had a fierce collision and conflict with the river. Perhaps it was in response to the police's high morale that the Cape Tongyi, who had been silent for 17 years, committed a crime again. As the only survivor of the serial murders, Oh Maria (Kim Min-jeong), comes into the sight of the police and the murderer, the long-standing Cape Child Case is about to come to a decision... This film is adapted from the "Hwaseong Serial Murder Case" which has never been solved in South Korea. The incident was made into a movie "Memories of Murder" and put on the screen.