As extreme cold freezes the surface, humanity is forced to move into underground cities. An ancient virus released during excavation combines with an electromagnetic pulse, disabling modern technology and turning the infected into living corpses. The surface is a death zone; underground is a living-corpse hell. The protagonist's System provides flawless logical guidance and pinpoints resources, making it the most powerful superbrain in the apocalypse, but every construction project still has to be carried out by the protagonist himself.
