In 2000, the Chinese nuclear experiment went wrong during transit, as a result of which Japan collapsed. Those who survived were posted on American military facilities based in Japan to avoid mortal radiation, and learned to live, following the regulated life of work and training. To facilitate boredom, a recreational preparation called "Zero" was illegally created and sold. Reception of the drug caused a dream, full of dreams, when people saw their lives as it was in 2000. And in cases of those who were not born until 2000? The maximum that they could assume is what they saw who they were in their past life, but it seems that something is brewing under the surface, and these past lives may contain a response.