World War Three wiped out the humankind. The planet is empty now. Huge cities became dust and ashes. Railroads are being eaten by rust. Abandoned satellites hang lonely in their orbits. Radio is mute on all frequencies. The only survivors of the last war were those who made it into the gates of the Metro, the subway system of Moscow city.
It's there, hundreds of feet below the ground, in the vaults of what was constructed as the world's largest air-raid shelter, where now people try to outlive the end of days. It's there that they created a new world for themselves. The stations of the Metro became city-states, and its citizens, torn apart by religions and ideologies, are fighting for now-scarce commodities: air, water, and space.