When someone dies in an grip of an powerful rage,The emotion becomes an stain of that place where they died.Death becomes an part of that,And if you cross it's path,You die.
Rika is a volunteer social worker charged with caring for Tokunaga Sachie, a catonic elderly lady. She discovers the quiet suburban home in a state of disarray and her ward malnourished and soiled, with no one else home. While vacuuming she finds a family picture with the wife's face cut out. Upstairs she hears shuffling noises coming from the bedroom closet, which has been taped shut. Rika removes the tape and opens the door when she hears meowing sounds. Inside the closet she discovers a black cat and a young boy whom she recognizes from the photo. She calls the welfare center to report the incident. She hangs up and is startled to see the boy staring down at her from the upstairs balcony. She asks his name. "Toshio" is his reply. Murmuring from Sachie's room draws Rika's attention. Rika attempts to calm Sachie, but is frightened by the sudden appearance of a dark shadow descending upon them. A pair of eyes appear within the shadow, which open and stare directly at Rika, who then faints. A human version of Toshio is seen standing next to her.
Kazumi, Katsuya's wife and Sachie's daughter-in-law, cannot sleep at night because of what she presumes to be Sachie's restless stirring. Kazumi reminds her husband as he leaves for work that his sister, Hitomi, is expected for dinner. She falls asleep on the couch and is startled awake. At first she assumes that it was Sachie, but soon sees a pair of fresh handprints on the door. She discovers a black cat on the stairs. When she approaches, a pair of small pale arms reach out and take the cat, which scares Kazumi.
Katsuya comes home to find his wife lying on the bed unable to move or speak. As he goes for the phone, he senses another presence in the room and soon encounters the boy, Toshio. Katsuya asks who he is, but gets no reply as the closet doors begin to shake and his wife's condition worsens.
Hitomi arrives for dinner only to find her brother sitting on the stairs behaving strangely and muttering something about a child that isn't his. She asks about Kazumi, but Katsuya will not say what became of her. Katsuya pushes Hitomi outside and tells her to go home.
Hitomi is one of the last people to leave the office building. She unsuccessfully attempts to call her brother on her way out. On her way out, she hears strange shuffling sounds in the corridor, which seem to be coming from behind her. Slightly unnerved, Hitomi stops in the ladies room, where her phone rings and identifies the caller as her brother. When she answers, a terrible death rattle sounds is heard coming from the mobile phone. In the stall next to her a provoking banging begins, Hitomi apologizes and hangs up the phone. A small teddy bear ornament falls from her purse as she begins to leave the bathroom. As Hitomi reaches for it the next door stall opens and an ethereal curtain of black hair moves ominously toward her making the same death rattle noise she heard during the mobile phone call. Hitomi runs to the security office and asks a security guard to investigate. She observes him, via a surveillance monitor in the security office, as he stops at the bathroom door the video camera footage begins to pick up little interference and a dark shadow emerges from under the door guiding the security guard into the room. Hitomi makes a hasty retreat to her apartment. At her home the phone rings and it ends up being her "brother" claiming to have forgotten the apartment number. Hitomi tells him the number, which is several stories up, and buzzes him into the building. Before she could hang up the phone her doorbell rings. She looks through the peephole and it's her "brother". She opens the door to nothing but an empty hallway, the death rattle sound comes loudly from the phone still in her hand. Hitomi quickly throws the phone on the hallway floor and heads back into her apartment, turns on the television, and cowers under the covers of her bed. The news is on but while the reporter is reporting the television picture and audio become distorted, the face warps into a phantom like image and the audio emits the death rattle sound and the television shuts itself off. Petrified, she continues to hide in her bed. Shortly after, she feels something strange in the bed and pulls it out, it's the teddy bear ornament that fell from her purse back at work. A human-shaped lump manifests from beneath the covers at the far end of the bed. Hitomi lifts the sheet to see the female ghost, who quickly pulls Hitomi towards her. A full shot of the room is seen and both the ghost and Hitomi are now gone.
When Rika does not return to the care center, her boss, Hirohashi, goes to the house to check on her. He finds Sachie dead and Rika in a state of shock. Detectives attempt to locate Katsuya by calling his cell phone. They hear ringing coming from upstairs and track the sound to the attic. There they find the bodies of the young couple living there, Katsuya and Kazumi. They also find out that every family that had lived in the house either died or disappeared. During the investigation, Hirohashi is found dead, and Hitomi is missing. The investigators turn to another detective, Toyama, for answers. Toyama was assigned to the case of a man, Takeo Saeki who had murdered his wife, Kayako, and child, Toshio, in that house years before. Toyama watches the security tape of Hitomi's office building and sees the security guard being consumed by a shadow and Kayako looking directly at the security camera. Convinced that the house is responsible for the rash of disappearances, Toyama goes there with gasoline, intent on burning it to the ground. He has a daughter, Izumi, who was about twelve years old. While inside he experiences a vision of her as a teenager. He is then attacked by Kayako. He manages to escape the house, but the two investigators who came to look for him are not so fortunate.
Several years later Izumi is a teenager and her father, Toyama, long since dead - another Ju-on casualty. As Izumi and two friends walk to school, she notices a missing persons poster featuring three of her friends. She was with them the day they disappeared from a house that was rumored to be haunted. Izumi feels guilty because she ran from the house in fear, leaving the others to their fate. At school the girls notice that there are no photos of Izumi from a recent event and complain to their teacher about it.
Izumi's state of mind has been deteriorating since the day they went to that house. She keeps the curtains closed, covers her head with a hood, and clutches a pillow. Her friends visit and are disturbed by Izumi's condition and the strange behavior of her mother. One friend draws the curtain to reveal that the windows are covered with newspaper. Izumi tells them the ghosts of her three missing friends are stalking her, peering at her through the windows. As her friends leave, Izumi's mother tells them her father had exhibited the same behavior before he died.
The girls remember the photos they brought to show Izumi. They understand why the teacher had not posted any photos of Izumi. In every photo, Izumi's eyes were eerily blackened out - as were the eyes of her three missing friends.
Back in her bedroom, Izumi is having a vision of her father. She suddenly wakes to find a scrap of newspaper on the bed and moves quickly to return it to the window. When she pulls the curtain, she sees her three missing friends, pale and grey, staring at her through the gaps in the newspaper. Terrified, she runs from her room, but the ghosts of her friends are in hot pursuit. Izumi runs into a room and attempts to block the doorway, but this does not deter the ghosts. Izumi, in a panic, backs away - right up against the Shinto altar in her house. Suddenly, ghostly hands, belonging to Kayako, emerge from the altar. Kayako proceeds to drag Izumi, kicking and screaming, into the altar as the ghosts of her three friends continue to approach. As the camera zooms in to the altar, the faces of Izumi and her father materialise in the darkness. In the bonus material of the DVD Shimizu explains that he intended on including the same effect happening between the shelves in the room revealing the faces of the three friends, but this idea was dropped because he thought it would either be ridiculed or take away the focus of Izumi's death and place it on the entire group.
Before her death it is made quite clear this takes place years in the future, not only because there is a scene with her father and her as a child, but not long before she dies her mother is watching the news. The report is on the discovery of Rika's dead body.
It is also theorized that she is an unmentioned character in the last vignette of Ju-On: The Curse 2 (the sequel to the telemovie) because it is titled "Saori," who is the name of one of her friends who disappeared in the Saeki house. Saori was the "ringleader" of the group.
Rika has more or less recovered from the trauma of her experience in the house. She arranges to meet an old friend, Mariko, for lunch. An old man plays peek-a-boo with an unseen person just outside the care center where she still works. Another worker, assuming the man is feeble-minded, tries to join in the game and is rebuffed. The old man resumes his game with his unseen playmate, a sight which makes Rika uneasy. Toshio reflection is visible in the glass, revealing the identity of the unseen playmate.
While having lunch with Mariko, Rika sees Toshio under the table, panics, and rushes out. Later Rika receives a call from Mariko, concerned over what had happened at lunch. Mariko tells Rika that she is on a home visit for a student who has not been to school. The student's name is Toshio.
Rika quickly realizes that Mariko is in the cursed house. She hurries there, but too late to help as Rika sees Mariko being dragged up into the attic. Rika briefly follows Mariko's path and sees Kayako crawling towards her. Rika panics and runs down the stairs to the door, but she runs past a mirror and sees an unfamiliar reflection where her own should be. She covers her face with her hands in the same way that the old man playing peek-a-boo did. Doing so reveals Kayako in the mirror, staring back at her through her fingers. After a frightening vision of Kayako emerging from her chest, Rika hears thumping noises overhead, and realizes that something is coming slowly down the stairs toward her. The ghost of Kayako, the murdered wife, inside a blood-soaked plastic bag is crawling toward her, long black hair covering her face. She seems to be reaching out for help. Rika covers her face with her hands again, and, to her horror, sees herself as Kayako (it is commonly mistaken that she is actually seeing Kayako without the blood, but this is not the case, it is really her but with Kayako's body and hair). It is then that Rika comes to the terrible realisation that she is destined to play out the curse.
After this revelation, Kayako disappears. More noises come from the stairs. Rika looks up to see a new spirit approaching: the evil Takeo Saeki, the killer of Kayako, and the source of the Grudge, striding slowly downstairs. Looking upstairs, Rika can see Takeo's son, Toshio, peering through the banisters, mirroring the same fashion in which Kayako was murdered. As Rika begins to protest, Takeo reaches for her and kills her off-screen (in a deleted scene, her death is shown in more detail - she is killed in exactly the same way as Kayako was).
The scene then fades to shots of the streets - abandoned and littered with 'missing' posters. The body of Rika is then seen, wrapped in a plastic bag, inside the attic, she has long hair now. As the camera zooms in on her face, her eyes open and the now-familiar croaking sound like Kayako. This scene is presumably set years later, perhaps in the same timeline as the "Izumi" chapter, as evidenced by the news report in that chapter.
- Megumi Okina as Rika Nishina.Rika is the first to discover the curse and must stop it befour the horror gets to her.
- Misaki Ito as Hitomi Tokunaga.Hitomi was cursed when she went for dinner.
- Misa Uehara as Izumi.Izumi was cursed when she and her freinds went to the house to hang out.However,Izumi escaped and is haunted ever since.
- Takako Fuji as Kayako Seaki.Kayako is the evil spirit in the film and kills anyone who crosses her path.Rika is the reincarnation of Kayako in the end.
- Yuya Ozeki as Toshio Seaki.Toshio is Kayako's son and is too an spirit.He haunts people with his cat noises and rarely kills like his mother.
- Kanji Tsuda as Katsuya Tokunaga.Hitomi's brother.Is cursed and is possessed by Takeo.
- Takashi Matsuyama as Takeo Seaki.Killed his wife and son and was killed in return.He kills Rika as the same way as Kayako.
- Kayoko Shibata as Mariko.Rika's freind.Is killed by Kayako at the end.
- Chikara Ishikura as Hirohashi.Rika's boss.He is found dead.
- Shuri Matsuda as Kazumi.Katsuya's wife.Is killed by Toshio.