[2] Two years after the events of Kamen Rider the First, a strange series of bizarre and gruesome murders occur, all connected to pop star Chiharu's song "Platinum Smile".

They begin their investigation by locating Chiharu's older brother Shiro Kazami, the former president of the rising IT enterprise ExaStream, whose staff disappeared two months prior.

After discovering one of his sister's imposters, Kazami finds Hongo and Ichimonji again and reveals he was the sole survivor of a Shocker experiment involving nanobots designed to convert all humans in Japan into cyborgs that claimed his staff.

With Chiharu's death, the "Platinum Smile" incidents seemingly end, Ichimonji leaves to spend his final moments at his favorite Ginza bar, Kazami decides to start a new life, and Hongo quits his job due to complaints about his saving Kotomi.

Because she left before Shocker quarantined the ExaStream building, Chiharu was unaware of her being infected until it was too late as her rivals pushed her down some stairs into a live electric circuit, severely disfiguring her face.

However, Tristar Promotions refused to make her death public, and used the very girls responsible for Chiharu's disfigurement to stand in for her as they release her final song, "Platinum Smile".

The song "Platinum Smile" soon after became a thing of urban legend, as Chiharu's "ghost" brutally murders those who listen to it, as well as those were covering up her demise.