Nightmare Detective

Nightmare Detective

Year: 2006

Runtime: 105 mins

Language: Japanese

HorrorThrillerCrimeMystery

You die in the dream, you die for real. When a number of suicide victims slash themselves in their sleep, detective Keiko Kirishima is called to investigate.

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Nightmare Detective (2006) – Full Plot Summary & Ending Explained

Read the complete plot breakdown of Nightmare Detective (2006), including all key story events, major twists, and the ending explained in detail. Discover what really happened—and what it all means.

The film opens with a tense, mysterious scene: a middle-aged man sits nursing a beer while a young man, Kyoichi Kagenuma, suddenly emerges from beneath the floor. The older man, Mitake, is revealed to be a former teacher of Kagenuma’s father, a connection that hints at a tangled web of family history and leverage. Kagenuma is tormented by the memory of a daughter his wife had aborted without his knowledge, a haunting guilt that weighs on him throughout the story. Mitake, portrayed by Shinya Tsukamoto, refuses to offer help, setting a foreboding tone that threads through the waking world and the dreams to come.

Kagenuma awakens in a hospital room beside Mitake’s body, surrounded by Mitake’s children. He had been inside Mitake’s dream, an inward journey meant to uncover who should inherit the man’s estate, but he cannot provide an answer. As he leaves, he discovers a chilling new power: he can telepathically hear the selfish thoughts of Mitake’s children. The foreboding realization sinks in that a messy legal battle over inheritance is about to erupt between the siblings, casting a pall over the family’s future.

Meanwhile, Lieutenant Keiko Kirishima, [Hitomi], has recently transferred from the National Police Academy to a district station. Her new colleagues—Detective Ishida, [Ren Osugi], and Detective Wakamiya, [Masanobu Andō]—don’t quite understand her, and their casual approach to crime scenes irks her. Kirishima’s sharp, prickly temperament makes it hard for her to mesh with the team, and she bristles at what she sees as a lack of professionalism. The atmosphere at the precinct grows tense when she finds herself at odds with Ishida, who mocks her discomfort at gruesome scenes.

Her first case involves a young woman found dead in her apartment, her body slashed and a blade placed in her hand. The door was locked from the inside, which leads Ishida and Wakamiya to conclude suicide; Kirishima remains unconvinced. There is no note, and a neighbor heard the victim crying out for help. A second, similarly disturbing case follows: a wife discovers her husband has slashed himself to death while asleep in their bed. Kirishima begins to sense a troubling pattern behind these incidents.

A startling connection emerges: both victims had dialed the same, unregistered number. The recorded conversations reveal a young woman repeatedly whispering “help me.” The team suspects hypnotic suggestion or some form of mind influence behind the deaths. The chief divides the investigators into two groups: a standard procedure team led by Ishida, and a second squad—led by Kirishima and Wakamiya—that pursues supernatural explanations. This division frustrates Kirishima’s rational approach, pushing her toward the possibility that there is more than a rational motive at play.

The two investigators turn to Kagenuma, known for his ability to enter and explore dreams. He is reluctant to assist, uncomfortable with using his power, and had recently attempted to take his own life—an act that neighborhood children narrowly prevented. The police press on, and Kirishima suggests dialing the mysterious number again. Wakamiya makes contact in the dream realm, but Kirishima senses something is deeply wrong.

Wakamiya falls asleep at the police station and is dragged into the dream world. Kagenuma, gaining confidence, finally enters Wakamiya’s dream and confronts the enigmatic figure, O. Wakamiya is killed, and Kagenuma is left injured and desperate to escape. Kirishima intervenes, forcing him to enter her dream as well; she warns him that he must save her, or she will die. Reluctantly, he decides to give it a try, while the other squad closes in on O in the real world.

As Kirishima edges toward sleep, she engages with O within the dream, seeking to understand how he can invade minds. O admits that his hunger to kill grew from a first victim and a rush he felt when he crawled into that person’s mind. He longs to feel that rush again and continues to slake that appetite by killing others, a cycle of compulsion that binds him to the waking world and the dream realm alike.

In the dream, Kirishima races through a derelict school, chased by a relentless inner voice that condemns her weakness. O finally corners her in a furnace, trapping her as Kagenuma arrives to challenge him. A buried memory surfaces for O: as a child, his teacher locked him in the same furnace that Kirishima is trapped in, alongside his sister who dies while trying to escape. The story reveals that the little girl who uttered the repeated “help me” is this sister, a memory that crystallizes the origin of the haunting and the predator’s hunger.

help me

In the end, the boundaries between dream and reality blur as Kagenuma unlocks this repressed memory, and Kirishima faces the darkest corners of her own psyche. The case spirals into a battle of wills between the dream-walker and the living, with the truth about Mitake’s past, the family inheritance, and the nature of O’s compulsion gradually surfacing. The film crafts a slow-burning, atmospheric examination of guilt, memory, and the uneasy alliance between empirical police work and the inexplicable forces that seem to govern human nightmare and desire.

Last Updated: October 09, 2025 at 16:44

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