The film is based on a true yet unsolved murder case from the early 1990s that is known among Koreans as the “disappearance of the frog children.” In 1991, five elementary school students told their parents that they were going to hang out on a nearby mountain to catch frogs, and then they go missing.

26 years ago, state troops were ordered to open fire on civilians in the city of Gwangju who were demonstrating as apart of a democratic movement. Thousands of civilians were killed. Now, a shooter from the national team, a gang member, a policeman, CEO from a large company and director of a private security outfit get involved in a plan to convict the person responsible for the massacre.

1986 Gyunggi Province. The body of a young woman is found brutally raped and murdered. Two months later, a series of rapes and murders commences under similar circumstances. And in a country that had never known such crimes, the dark whispers about a serial murderer grow louder. A special task force is set up in the area, with two local detectives Park Doo-Man and Jo Young-Goo joined by a detective from Seoul who requested to be assigned to the case.