At the beginning of the movie, homicide detectives are in hot pursuit of a serial killer. Officer Seung-hyun arrives at a hideout ahead of his partner but is caught off guard, stabbed, and left to bleed out. Just before his final moments, he informs his partner that four people are behind the brutal killings.
Shortly after, Jae-hwan receives an anonymous tip-off about the location of the serial killer, Jin-hyuk, who is the ringleader of the murderous gang. The police immediately gear up for action, with Jae-hwan cautioning Min-seong to remain vigilant and follow his lead.
A serial killer’s mind trapped in a detective’s body (Photo: Devils/Warner Bros.)The team storms the location only to find Jin-hyuk in the middle of dissecting a corpse. On sighting the officers, he takes to his heels. Jae-hwan and Min-seong spring into action, pursuing him. Jin-hyuk manages to get into a vehicle and speeds off, forcing Min-seong to hop into another car with Jae-hwan as they give chase.
At a critical moment, the officers see an opening and swerve in front of Jin-hyuk’s vehicle, causing a violent crash. Jin-hyuk, however, manages to wriggle out of the wreck and continues fleeing on foot. While Jae-hwan struggles to keep up, Jin-hyuk halts momentarily when he reaches the edge of a steep slope.
Seizing the opportunity, Jae-hwan lunges at him, sending them both tumbling down. Since the chase happens in a dense forest, it takes time for the other officers to reach them. Min-seong calls out to Jae-hwan, but there is no response.
By the time the rest of the officers arrive, they realize both Jae-hwan and Jin-hyuk are nowhere to be found. A thorough search is launched, prioritizing Jae-hwan’s rescue. Days turn into weeks, but there is no sign of him.
The police set up a base nearby, hoping to find him soon. Jae-hwan’s wife and daughter visit the site, where the lead officer reassures them that he will be found. Despite the promise, months pass with no breakthrough.
As the authorities begin pulling back resources, the killings resume, leaving Jae-hwan’s family devastated. Then, in a shocking turn of events, a car crashes into the police station, and inside, officers find both Jae-hwan and Jin-hyuk—injured and unconscious.
They are immediately rushed to the hospital. When Jin-hyuk regains consciousness, he is bewildered to find himself restrained to the hospital bed. He soon realizes that his consciousness has been swapped into Jae-hwan’s body.
Meanwhile, Jae-hwan, now trapped in Jin-hyuk’s body, is left helpless as his worst nightmare plays out before him.
Jae-hwan Struggles to Prove His Identity
Jae-hwan (in Jin-hyuk’s body) desperately tries to convince the officers that he is not the criminal they believe him to be. Unfortunately, his pleas fall on deaf ears. With no other option, he confides in Min-seong, who is sceptical at first.
To test if the claim holds any truth, Min-seong tries different methods to verify whether the man before him is truly Jae-hwan. Slowly, he starts believing him, though he remains cautious. On the other hand, Jin-hyuk (in Jae-hwan’s body) uses his new identity to his advantage, slipping seamlessly into Jae-hwan’s life at work and home.
He even visits Jae-hwan (in Jin-hyuk’s body) in custody and presents him with a deal: reveal everything about his past, or his wife and daughter will suffer. Under immense pressure, Jae-hwan starts sharing details about his life.
As the police prepare to transfer Jae-hwan (in Jin-hyuk’s body) to a detention center, he stages an escape by injuring himself. Once free, he begins tracking Jin-hyuk (in Jae-hwan’s body), only to find him enjoying life with his family.
Jin-hyuk extends an offer—if Jae-hwan (in Jin-hyuk’s body) delivers the remaining three members of the gang within two weeks, he will return his body. To get him started, he provides a clue about the whereabouts of the first target.
Hunting Down the Criminal Gang
With Min-seong’s assistance, Jae-hwan (in Jin-hyuk’s body) tracks down an elderly gang member and subjects him to intense questioning. The man confesses to his past crimes and exposes the location of the next accomplice.
Jin-hyuk (in Jae-hwan’s body) also visits the old man, revealing that their bodies have been swapped, which leaves him in utter disbelief. At the next destination, Jae-hwan (in Jin-hyuk’s body) and Min-seong encounter a more formidable adversary.
The confrontation escalates, leading to Jae-hwan being captured and hung upside down. The criminal, unaware of the body swap, taunts him, stating that he will be tortured like all previous victims. He proceeds to cut into Jae-hwan’s leg, causing excruciating pain.
At this point, memories begin to resurface, taking the story back to the day Jae-hwan and Jin-hyuk were separated from the police. Determined to extract a confession, Jae-hwan had taken Jin-hyuk to an isolated location, resorting to extreme torture methods.
He even attempted electric shocks, but Jin-hyuk refused to break. At one point, Jin-hyuk tried to bite off his tongue, but Jae-hwan intervened. Instead of feeling intimidated, Jin-hyuk laughed hysterically, relishing the chaos.
To gain an upper hand, Jae-hwan sought advice from a trusted colleague, who introduced him to an outlawed CIA interrogation technique. Using this approach, Jae-hwan implanted the idea into Jin-hyuk’s subconscious that he was, in fact, Jae-hwan, setting the stage for the eventual body swap.
Now, in the present, Jin-hyuk remembers everything and mercilessly eliminates another gang member.
A Fatal Miscalculation
Min-seong arrives at the scene, comforting Jin-hyuk under the false impression that he is Jae-hwan. At that moment, Jin-hyuk grins, revealing the truth before killing him. The police later discover the bodies, while Jae-hwan faces Jin-hyuk once again.
This time, Jin-hyuk feigns weakness, pretending to be affected by the drugs. He convinces Jae-hwan to locate the last gang member, Yo-han. When Jin-hyuk meets Yo-han, he quickly overpowers him, but Yo-han has already alerted Jae-hwan.
The final confrontation takes place inside a van where previous captives were tortured. Jin-hyuk demands to have his body back, but as music plays in the background, he starts laughing. With his memories fully intact, he confesses to killing Jae-hwan’s brother, Seung-hyun, which sends Jae-hwan into a rage.
Was Justice Served?
The battle between Jae-hwan and Jin-hyuk reaches its climax, but Jin-hyuk gains the upper hand by injecting Jae-hwan with a sedative. As police officers surround the van, Jin-hyuk manipulates Yo-han into believing that Jae-hwan is the real Jin-hyuk.
A pursuit through the forest ends with a horrifying mystery (Photo: Devils/Warner Bros.)He steps outside and pretends to be Jae-hwan, recounting details from Jae-hwan’s life to confuse the officers. As Jae-hwan staggers out, he desperately tries to convince his colleagues of the truth. He grabs a knife, intending to put an end to Jin-hyuk, but the officers warn him to stand down.
Ignoring their commands, he moves to strike, prompting his team leader to shoot him. Despite his injuries, he continues attacking Jin-hyuk until another round of gunfire brings him down. Even with his wounds, Jae-hwan succeeds in killing Jin-hyuk.
The officers check his condition and quickly call for an ambulance, leaving the audience with a tragic yet decisive ending.
A High-Stakes Thriller from Start to Finish
Right from the opening scene, Devils maintains a gripping pace, never dragging out suspense unnecessarily. The psychological battle between Jae-hwan and Jin-hyuk keeps the tension high, making every moment intense. What makes the story even more chilling is how Jin-hyuk weaponizes Jae-hwan’s tactics against him.
Rather than being upfront with his team or family, Jae-hwan’s secrecy becomes his downfall. Another striking element is how the colleague who introduced Jae-hwan to the CIA methods remains absent when he needs help the most.
The film paints a picture of a detective so consumed by his mission that he fails to see the danger lurking within his own choices.
