In 2066, the world entered the "grey fog era". The sun went out and a gray-white fog enveloped the earth.
As long as humans stay in the fog for more than ten minutes, the retina will undergo changes (red spots will appear), and then indescribable "dirty things" will be seen.
The official definition is: first-level pollution (visual distortion), second-level pollution (physical distortion), and third-level pollution (mental breakdown).
The order collapses, and the only rule for survival is: either you eat it, or you are eaten by it.
