At the age of nineteen, Sadako joined a Tokyo-based acting troupe. As revealed in the short story "Lemon Heart", she fell in love with the sound operator, Hiroshi Toyama. He learned of her powers but accepted them. Unfortunately, an early form of the curse was created in the form of a sound recording which killed four people, including the troupe's director, resulting in a heartbroken Sadako leaving Toyama. Eventually, Sadako visited Ikuma in the Izu sanatorium, only to be raped by a doctor named Jotaro Nagao, who contracted smallpox at the time. However, he discovered that she had Testicular Feminization Syndrome, possessing the genitalia of both sexes. Sadako then bit him in the shoulder, causing her to be infected by the smallpox virus that Nagao contracted. Finally, Nagao threw her down a nearby well and sealed her within. Foreseeing herself being reborn years later, Sadako vowed revenge on the world before she died. Her psychic powers mutated the smallpox virus into a new strain of virus, called the "ring virus", one that would cause anyone who contracted it to die within a week.