Darkness

The 2015 NaNoWriMo Tablo.io Novel Writing Contest winner.
A virus decimated the entire planet's human population. No treatment or vaccine could be found, so contraction-meant death.
Humanity was forced to seek refuge in hermetically sealed self-sustaining bunkers, commonly referred to as 'biospheres'. After the world's power grid failed, survivors managed to establish a global satellite communications network, which allowed them to weave together a digital facsimile of their once thriving, but now extinct way of life.
The disease, however, remained active and continued to spread, despite the survivors best intentions and inexhaustible precautions. It was therefore commonplace for connections to become broken, from time to time. The people of the network began to call the silence that inevitably came at the end of the line-The Darkness.
No one ever returned when The Darkness came to call.
Until now...