When Sadako was a young girl, she was very melancholy and depressed. She seldom spoke and never played with other children, spending all of her time alone.
Sadako's mother was a psychic and she conducted several experiments with a psychic researcher named Dr Fukurai. When the doctor published the results of his experiments, other scientists accused Sadako's mother of being a fraud and said she faked her psychic abilities.
Sadako's mother was so distraught by all the criticism that she committed suicide.
Sadako was devastated by her mother's death and lived with her father on a remote island. As she grew older, she began to develop psychic powers of her own. When her father learned of her psychic powers, he brought her to Dr. Fukurai in Tokyo.
The doctor forced Sadako to participate in many experiments that involved using her mind to make words and images appear on photographic film. In Japan, they call this "Nensha" which means Thought-photography or Thoughtography. Sadako produced a number of these "thoughtographs" and nobody could explain how it was done.
Dr Fukurai wanted to publish another book, but remembering what had happened to her mother, Sadako refused. She told him she was going to leave and would never return.
Nobody knows for sure what happened after that. Some people believe that the doctor murdered Sadako. They say he lured her out to the woods near the hospital and strangled her. Then, he threw her body down a nearby well and sealed it with large rocks to keep her hidden forever.
However, Sadako was not really dead. When she woke up, she was trapped in the well and couldn't get out. She attempted to escape by scaling the walls but failed every time, breaking off her nails and fingertips in the process.
The poor girl survived in the well for seven days before she finally died with her heart full of hate. With her last breath, she vowed to have her revenge on the world.
Sadako's rage and terror and the manner in which she died combined with her psychic powers to create a terrible curse or "grudge". This resulted in a series of inexplicable images being projected onto a mysterious unmarked videotape.
Sadako appears in the videotape as a shadowy young woman dressed in a white gown. Her face is covered by long black hair. They say that if you watch the video, you will die in seven days.
The only way to avoid the curse is to make a copy of the videotape and give it to somebody else.