Sim Deok-su, Baek Yoon-sik, is a grumpy landlord who rules over a string of cramped, working-class flats with a hard hand and a sharper tongue. His days begin with a blunt demand for rent, and his reputation—a kind of Scrooge-like sneer—makes him widely despised in the neighborhood. He moves through his routine with clinical detachment, paying little mind to the struggles of those below him, including a sick tenant named Mr Choi who has already fallen on hard times. As Deok-su goes about his business, police work is quietly unfolding around him: two dead bodies are found and cleared, one belonging to a local drunk and the other to an elderly pensioner living alone. The sense that something more sinister is at play lingers in the air, even as Deok-su returns to his own bickering world of rent and reproof.
That night, in Mr Choi’s apartment, the weary man who once wore a badge reveals himself to be more than just a sufferer of life’s misfortunes. He was a police detective in his prime, and his mind still races with theories. He insists that the earlier deaths were not accidental, but murders that seem to follow a grim pattern—a killer who started with the elderly and appears to be moving toward younger victims. The two men talk through the clues, their conversation weaving together memory and motive, until Mr Choi’s voice falls silent and the room grows heavy with unspoken worry.
The very next hours bring a brutal turn: Mr Choi is murdered, staged as a suicide, and a second murder erupts in the corridor—Ji-Eun, a diligent and quiet textile mill worker who lives in Deok-su’s building, discovers her roommate dead with her throat slit and then is dragged into a nightmare when the killer strikes again and abducts her. The neighborhood quickly pins the blame on Deok-su, a move built on fear and the perception that his earlier encounter with the church volunteers marked him as sinister. Yet the one person who refuses to swallow the narrative is Mr Choi’s former partner, retired Detective Pyung-Dal, Sung Dong-il. He arrives with old instincts and fresh proof, showing that Choi’s death was not a suicide and revealing a chilling history of similar murders that had rocked the area thirty years earlier.
With this new evidence, Deok-su begins to see a possible target in Ji-Eun, who fits the killer’s pattern from the long-ago cases Pyung-Dal has recounted. He hurries back to her apartment to check on her safety, a move that sets off a new chain of confrontations. A tense confrontation with a gang of young thugs, one of whom is linked to the murdered young woman, escalates the danger. When Deok-su and Pyung-Dal push forward into Ji-Eun’s space, they unearth a gruesome shock—the severed head of Ji-Eun’s roommate rests in her refrigerator, a macabre sign that the threat is closer than anyone realized. The seasoned detective reads the room and, urging caution, persuades Deok-su not to alert the police just yet, fearing the killer’s reach could endanger Ji-Eun herself.
From there, the two men fuse their nerves and competencies, chasing down every crumb of evidence, following a path that twists through the building’s halls and into the lives of those who seem ordinary on the surface. Their alliance thickens as they move from suspicion to pursuit, each clue pulling them deeper into a maze of secrets, past loyalties, and long-buried memories. The pursuit grows increasingly perilous, and the question of who truly deserves trust becomes more urgent with every turn.
In the culmination of a labyrinth of revelations, the identity of the killer comes into focus: a mild-mannered doctor who has earned the town’s trust through his quiet volunteer work and his devotion to his paralyzed wife. Behind the veneer of gentleness lies a calculating mind, and the doctor’s everyday kindness hides a chilling capacity for violence. The revelation reframes everything Deok-su and Pyung-Dal have learned, forcing them to confront the true cost of a past that never truly rested and the danger that can bloom when a person’s darkest impulses go unchecked. The film leaves viewers with a stark look at how the calm surface of a small community can mask a web of secrets, and how the most unexpected people can become catalysts for tragedy—and for vigilance that refuses to blink.
