Children…

On March 26, 1991, five boys vanish while exploring a mountain on a day off from school. Their parents push for an immediate police investigation, but authorities are distracted by safeguarding polling stations. Thousands of officers scour the mountain, yet no clues materialize, and the nation watches with growing dread.

The disappearances capture hearts and minds as theories surge from North Korean spies to alien abductions. Families campaign tirelessly for answers, and the case becomes a nationwide obsession. The authorities are stretched thin and the truth remains elusive.

In 1996, Kang Ji-seung, a documentary maker who has just been reassigned after a career setback, returns to a small town to rebuild his name. He teams up with professor Jeon Kuk-hwan, who hopes to prove himself by solving a crime the police could not. The partnership begins a renewed look at old clues with fresh eyes.

The professor's theory gains traction after uncovering a telephone recording of a boy claiming to be one of the missing children calling his own home. The mother's reaction unsettles the investigator and hints at secrets the family might be concealing. Authorities agree to investigate the boy's home again, though nothing conclusive is found.

As the investigation presses forward, the entire household—parents and even the grandmother—appears reluctant and unsettled. The family's reputation is shattered, and the father dies without ever clearing his name. The professor loses his university position as the case drains both men of their standing.

In September 2002, the remains of the children are discovered in the woods on the mountainside they described visiting. Two skulls show large holes and one bears indentations from an unidentified instrument, while their clothes are tied with sailor knots and bullet casings are found at the scene. The discovery shocks the country anew.

Soon after the discovery, Seoul is rattled by news of two more children missing in the capital. The country contends with renewed fear and a reminder that the killer may still be at large. The case reignites public demand for answers and accountability.

Kang Ji-seung reconnects with the police officer who investigated the original disappearance. He learns of a mysterious young man who is always seen fishing nearby, suggesting a connection to the crimes. The officer admits he kept silent to see if another crime would yield an opportunity to trap the suspect.

Using a traced license plate, Ji-seung locates the suspect and breaks into his apartment while he is away. He finds a disturbing cache of items belonging to children and stacks of books tied into sailor knots. He waits outside the building, intending to confront the suspect when he returns.

The next morning, Ji-seung’s daughter vanishes and reappears moments later claiming a passing truck helped her. He races the truck to a slaughterhouse to confront the suspect, who refuses to confess but hints that he might be the killer. With no solid evidence, the confrontation leaves the case unresolved.

The suspect offers no confession and the evidence remains inconclusive, leaving the case unresolved. The city continues to fear that the killer is still active, and the investigation lingers in memory. The pursuit of truth clashes with the limits of justice.

The case endures as a careful balance between truth and justice. Investigators chase threads that refuse to untangle, while the public memory of the disappearances shapes future inquiries. The story closes with a haunting sense that some questions may never be fully answered.