There was a rumor today that rumblings had been heard at Zulof - a town only 30 km from my own. Worried whispers could be heard as I went to the market for supplies - how long? how deep? - but no one knew the answers. The automatic tunneling machines had been turned loose long ago, with nuclear engines and a directive to never stop, to keep connecting the cities of the world.

Too late the Engineers realized their inertial guidance systems were drifting, as swathes of cities collapsed into tunnels cut too shallow. The tunneling machines could not be stopped or reprogrammed, to prevent nation-states from turning them to their own whim, but now they acted as agents of terror by their own accord.

Those 30 km could be cut in a day or a week, depending on the hardness of the rock and the condition of the machine. It would score through the town, wreaking havoc as it went. My plan was to camp in the mountains for a week or two, if the market had enough supplies. Chances were high that others had the same idea.