It was noon but there was no sun in the starlit sky. Many weeks before the sun had slipped below the southern horizon. For a little while a dim halo had marked its passage each day; then that, too, had faded away. But now it was time for the halo to appear again, to herald the sun’s returning.

Frost filled the sky, making the stars flicker as it swirled endlessly downward. He blinked against it, his eyelashes trying to freeze to his lower eyelids at the movement, and turned to look at the north.

There the northern lights were a gigantic curtain that filled a third of the sky, rippling and waving in folds that pulsated in red and green, rose and lavender and violet. Their reflection gleamed on the glacier that sloped down from the caves and glowed softly on the other glacier; the one that covered the transmitter station. The transmitter had long ago been taken into the caves but the generator and waterwheel were still there, frozen in a tomb of ice.