Time of Isolation

Sampson sighed. This paperwork is driving me crazy. Why do we have it anyway? He imagined that somewhere underneath their city there had to be a depository where all of this useless stuff was stored. He suspected it would probably be, enough to heat all the areas for many generations. That of course if they needed heat. Still theirs was one of the many cities hidden deep inside the desolation. So, heat was the last thing they needed. He looked up and saw one of the under-workers approaching, and paused. It was obvious she wanted to talk. "Yes?"
"Sir, we just received word that Terra has gone silent, and since we are the closest, we need to try and reestablish contact with her."
Another one, he thought. What's going on? Standing he sent the signal for the team's attention. "We have another city that has gone silent and we are the closest. Let's get to it and see if we can reestablish communications. I don't have to tell you how critical this is. On the board will be the emergency frequencies, and codes. Let's get to it!"
Theirs is one of the many advanced cities hidden deep inside the desolation. An area where nobody should be, able to live and it is this reason they are, unknown to the outside world of the primitives. In comparison, their population is small, and as such, if they were ever, discovered it is, feared they would be, destroyed. Yet, there would be no reason for the primitives to enter the desolation. To them it is death, a place, where their gods and the spirits of the dead reside. A place to shun. So if not the primitives, what is it that's causing cities to go dark?