Sadako Yamamura's body is pulled from the old well, and the authorities enlist her uncle Takashi Yamamura to confirm the corpse’s identity. Detective Omuta delivers the sobering news: forensics suggest Sadako survived in that well for thirty years, a revelation that compounds the guilt Takashi Yamamura has carried since Sadako’s mother, Shizuko Yamamura, took her own life amid a cascade of past actions. The remains are eventually entrusted to the uncle, who chooses to lay them to rest at sea in a bid to absolve himself of the heavy burden he bears.
In the wake of tragedy, Reiko Asakawa's world unravels as she learns of the sudden deaths of her ex-husband, Ryuji Takayama, and her father, Kôichi Asakawa. The police close in on Reiko and her young son, Yoichi Asakawa, as investigators assemble a timeline that begins with a burned videotape found in Reiko’s apartment. Mai Takano, a former colleague of Reiko, teams up with Okazaki to chase leads that might explain the eerie connection between the deaths and the tainted media.
Their search leads them to the urban legend of the cursed videotape, drawing them into a chain of encounters that include Kanae Sawaguchi, a high school student who witnesses the tape’s power and reluctantly hands a copy to Okazaki. Kanae begs him to watch it before the week is up, a plea that sets off a dangerous countdown. Meanwhile, Masami Kurahashi, once a friend of Reiko’s niece Tomoko, has become mute and frightened of televisions, a consequence of witnessing the film’s ripple effects. Her physician, Dr. Kawajiri, a paranormal researcher, attempts to purge the psychic energy that clings to Masami through experimental means, hoping to sever the haunted tether between the living and the dead.
Mai, drawn deeper into the mystery, confronts Masami and experiences Sadako’s presence on a television screen that terrifies the hospital’s inhabitants. Masami’s fear appears to funnel psychic energy toward Mai, hinting that Yoichi’s own latent abilities may be intensifying. As Mai and Yoichi reconcile with the increasingly dangerous reality, they realize Kawajiri’s work has consequences: when Kawajiri applies a method to exorcise the energy, the cursed imagery leaks onto a blank tape, resurrecting Sadako’s haunting visuals in the process. In a tense turn, Mai destroys the recording, yet the danger remains. Omuta’s interrogation intensifies, and Mai is coerced into revealing Reiko and Yoichi’s whereabouts, forcing her to witness Kanae’s terrified corpse in a harrowing moment of guilt.
With danger closing in, Mai telepathically urges Yoichi to flee the police station. The pair escape as Yoichi unleashes his burgeoning powers in a defensive psychic assault on the officers. Back on their trail, Okazaki attempts to erase an interview with Kanae, but Kanae’s ghost materializes, leaving an unmistakable and chilling trace of revenge.
Mai and Yoichi retreat to Oshima Island, seeking shelter at the Yamamura Inn. A nightmare thrusts Shizuko’s specter and a young Sadako into the night, and Mai seeks Kawajiri’s help once more. She volunteers to act as a conduit, directing Sadako’s hatred into a swimming pool, where water is believed to neutralize the malevolent energy. The ritual turns catastrophic when Sadako’s coffin rises from the pool, and Takashi Yamamura dives in, intent on being claimed by Sadako himself, while Kawajiri follows with improvised electrical gear, both men losing their lives along with their assistant.
The spellbinding peril continues as Mai and Yoichi fall into the pool and surface inside the well. Ryuji Takayama ghosts lunge to absorb Yoichi’s fear and conjure a rope that might guide Mai to safety—provided she can resist looking down. The well reveals Sadako’s cryptic query, “Why is it only you were saved?”, as the two manage to crawl ashore and emerge, gradually freed from their fear. In the aftermath, Okazaki ends up institutionalized, while a nurse glimpses something unsettling in a developing photo: behind Okazaki, Kanae’s laughing spirit lingers, utterly bent on revenge.
