A perfect painkiller with no addictive qualities or side effects, named NSTRA-14, was developed. As this painkiller became commonly used, the perception of pain shifted. Pain vanished, but ironically some people began to actively pursue pain. A religious cult emerged, asserting that experiencing pain is what makes humans more humane. They believed that eradicating pain is equal to annihilating the soul, rejecting God, and desecrating salvation. Eventually, the cult blasted the building of the pharmaceutical company that developed NSTRA-14 with a drone attack. Kyeong, the daughter of the company’s owners, lost her parents in the incident, and Tae, who carried out the attack on the cult’s orders, confessed to all crimes and was sentenced to life in prison.

Twelve years after the terrorist attack, two former followers of the cult are found murdered. Both had previously served time for their involvement in the attack. Their bodies bear signs of torture, and the illegal drug that had been used by the cult twelve years ago is detected. Additionally, a piece of printed paper is found with the words,

“The dead have already been saved.”

The police retrace the case from twelve years ago to identify the killer. Since the drug detected in the dead bodies is not available today, their only option is to revisit the site of the incident twelve years ago in search of clues. Detective Ryun and Detective Soon board a private plane provided by the pharmaceutical company and head to the wasteland where the attacked building is located, accompanied by Tae who has been serving his sentence, Hyeon, the current president of the company who arranged the transportation, and Kyeong, the only person knowledgeable about the drug. Every night, Kyeong visits Tae, the nemesis of her parents, and sleeps with him. Their sexual encounters are one-sided with Tae’s hands bound in handcuffs and Kyeong assuming control. Kyeong does not explain her actions to Tae who obediently complies with her desires. Both of them are covered in scars all over their bodies. Tae endured countless tortures in the cult under the guise of transcending pain, while Kyeong suffered from her parents’ drug experiments and attempted suicide. Their loveless sexual encounter, marked by their shared sufferings, evokes a sense of sadness.

Tae insists that meeting his older brother Han, a high-ranking member of the cult, will lead them to the killer. The detectives follow his lead and head to a lakeside cabin near the old pharmaceutical company building. At the cabin, they encounter Han, Wook, and Min. The detectives apprehend Han and Wook, who fiercely resist, and bring them to the police station for questioning. However, the investigation yields no fruitful results, so the detectives release them. The following day, a third body is discovered. It is Wook, found dead at a bus stop right in front of the police station. Detective Ryun decides that the case has now become too grave for civilians to be involved and tells Kyeong and Hyeon to take the private plane to go back. Unfortunately, this area is prone to frequent tornadoes. Due to an impending tornado, the plane is grounded, leaving Kyeong and Hyeon trapped in the hotel. Meanwhile, near the lake, the detectives are investigating a wasteland that was abandoned when the pharmaceutical company withdrew. They suddenly experience a horrifying hallucination, witnessing piles of corpses and the ground crumbling beneath their feet. When they regain consciousness, they stumble upon an illegal drug manufacturing facility and unexpectedly encounter Han, who has been hiding out since his release from the police. Han vehemently denies being the killer, but a mountain of evidence points to him as the culprit. The detectives take him into custody. Just before the tornado hits, a fourth murder occurs. The fourth victim is revealed to be Han, who was previously imprisoned in the detention center. Determined and upset, the police meticulously examine the CCTV footage to investigate the whereabouts of everyone, but everyone has a solid alibi, except for one person: Yeop, a psychiatrist in charge of Tae.

Just as they are about to review the CCTV footage featuring Yeop, the tornado strikes, causing a power outage in the building. After some time, the tornado subsides, and the power is restored, but Yeop is nowhere to be found.