Day by Night — Tanith Lee

The planet did not rotate. On one side eternal day, the sun shining down hotly from the center of the heavens. On the opposite side eternal night, the stars glowing cold in the black and airless sky.

Yet the planet had been colonized. In ages past civilization had dug into the rock of the darkside and had thrived. Aristocrats vied with aristocrats, and the poor, as ever, struggled to keep home and body together against the ever-encroaching cold surface.

To keep the lower classes happy, Vitra, the storyteller, spun romantic sagas on the popular network. She imagined a strange world on the sunside, inhabited by men and women enmeshed in crime and love, schemes and intrigues.

Vitra believed she was making this up. But was she? Was there really another civilization on the bright side and could it be that what she related was not fiction -- but events which would inevitably send both worlds out of synch to mutual disaster?