Shizuko Yamamura develops psychic powers, and predicts the eruption of Mount Mihara on Oshima Island, which erupts on the exact date and time she predicted.
Shizuko begins talking to the ocean. Her cousin Takashi Yamamura listens to her and realises she is not speaking a human dialect. She seems to cause trouble for local fisherman with her psychic powers.
She mysteriously becomes pregnant. She goes off on her own when she goes into labour, giving birth to Sadako by a cave shrine called the River of Offering. Shizuko then returned home, claiming she had placed Sadako into the ocean.
The day afterards, Shizuko retreives her baby.
Shizuko goes to Tokyo at some point and meets Doctor Heihachiro Ikuma, a doctor at Tokyo University. He becomes interested in her powers, and the two eventually fall in love.
Dr. Ikuma, Shizuko and Takashi set up a public demonstration for the press of Shizuko's psychic powers. Sadako also comes along. Unfortunately, during the demonstration a journalist Miyaji accused Shizuko of being a fraud. An angered Sadako killed him using her own psychic powers via a heart attack. This causes Sadako to split into two identical girls, one good, one evil. Shizuko is affected afterwards and slowly goes mad.
One of the Sadakos goes to school. During a trip to the ocean, Sadako warns that the swimming team will drown if they go in the ocean. Her prediction comes true.
It is revealed in Ring 0 that all the journalists who attended Shizuko's demonstration have died, caused by the first form of Sadako's curse, an audio recording of the demonstration's events.
Sadako's teacher visits the Yamamura Inn, witnessing Shizuko brushing her hair for a length of time, and then encounters both Sadakos.
Shizuko commits suicide by leaping into Mount Mihara. Dr. Ikuma and the two Sadakos move to Izu.
The evil Sadako is drugged by Dr. Ikuma and locked in a room in Ikuma's home so she does not grow. The good Sadako is allowed to live a normal life.
Last Week of August: Tomoko Oishi, her boyfriend Iwata and two other students spend the weekend at the Izu Pacific Land Resort, where they accidentally watch Sadako's cursed videotape, created by Sadako using her Nensha powers. Sadako has died at this point but risen as a ghost.
September 5th: A week later, Tomoko tells her friend Masami Kurahashi of her experience and is killed by Sadako's ghost. Masami witnesses this and is hospitalised.
September 11th:Reiko Asakawa and Yoichi Asakawa, Tomoko's aunt and cousin, attend her memorial service. Reiko is asked by her aunt to investigate Tomoko's death.
September 13th: Reiko goes to Izu after some investigating and watches the tape.
September 14th: Reiko enlists the help of her ex-husband Ryuji Takayama to analyse the tape, which he watches.
September 15th-19th: Reiko and Ryuji investigate the tape, eventually learning the woman on the tape is Shizuko Yamamura and lived on Oshima Island. Yoichi watches the tape when Tomoko's ghost tells him too, forcing his parents to go to the island and confront Takashi Yamamura. Reiko realises Sadako's body is in Izu, Takashi using his boat to take the back to the mainland. Reiko and Ryuji find the well Sadako is trapped in and recover her corpse.
September 20th: Ryuji is killed by Sadako. Reiko salvages his copy of the tape and realises she must show it to someone else to save Yoichi.
September 22nd: Reiko takes the copy to her father Koichi Asakawa and asks him to watch it to save Yoichi.
September 28th: Koichi dies from the curse, Reiko and Yoichi fleeing to the city.
September 29th:Mai Takano and Okazaki start looking for Reiko and clues to Ryuji's death. Koichi's body is found and removed by the police, who are also looking for Reiko. Police forensics specialist begin to rebuild Sadako's head.
September 30th: Mai spots Reiko and Yoichi in Tokyo, but is unable to find them. Okazaki interviews student Kanae Sawaguchi about the tape and asks her to get him a copy. Mai and Okazaki learn of Masami and Tomoko, visiting Masami in hospital. They meet Dr. Ishi Kawajiri who studies paranormal research and explains Masami has developed Nensha powers. Masami ventures out of her room but causes a telekinetic incident and is put in restraints.
October 1st: Mai reunites with Reiko and Yoichi, who has now become a mute. Kanae gives Okazaki a copy of the tape but reveals she has watched it. Fearful, Okazaki hides the tape in his newsdesk draw and locks it.
October 8th: Mai visits Dr. Kawajiri to tell him where Reiko is but finds Masami is to be used in an experiment to transfer Sadako's powers onto a blank tape. However, the attempt goes wrong and Masami is killed. Later that night, Kanae is killed by Sadako. Mai is forced to reveal Reiko's location, and she is taken in for questioning. Mai manages to telepathically tell Yoichi to flee with Reiko, but outside, Reiko is hit by a truck and dies. Okazaki tries to destroy his interview tape with Kanae, but she rises as a Yurei ghost.
October 9th: Sadako's body and reformed head are given to Takashi, who places his niece's coffin in the sea. Mai and Yoichi go to the island, where Yoichi is haunted by Sadako's powers. Dr. Kawajiri arrives.
October 10th: Dr. Kawajiri decides to retry his experiment to save Yoichi and remove Sadako's powers from him. At a swimming pool, the experiment backfires again. Sadako's coffin appears in the pool and opens, Takashi jumping into the water to sacrifice himself to Sadako to spare the other but Dr. Kawajiri commits suicide and his nurse assistant Hayashi dies too. Mai and Yoichi find themselves in the well where Ryuji's ghost appears and absorbs Sadako's power and Yoichi's rage from his son. Mai and Yoichi try to flee the well via a rope, but Sadako appears and asks why she cannot escape before succumbing to her fate. Mai and Yoichi escape unharmed.
October 11th: Okazaki's copy of the tape is found by colleagues in his desk. Okazaki is hospitalised and tormented by Kanae's ghost.