Henry felt let down, cheated. It was just an empty building containing soundless machinery and a recorded lecture. No Old Ones. Nothing he wanted.

"Now behind you," the voice began again, "you can see into the Control Room. From there every machine, store or house can have its power cut on or off. And if anything goes wrong with its circuit a button on the board flashes red until it is repaired. The glowing red button close to the window is the master switch that will shut off everything in case of an emergency, such as an earthquake."

Theta pressed her nose to the glass window. "Just think," she breathed, "push that and everything stops!"

Perhaps that's what happened in the other valley, thought Henry. Someone pushed the red button ... then couldn't get things going again.

"Now follow the line to the next room and be seated. There you will be shown how the complex of the valley was constructed and how it operates."

On entering the hall they found several rows of seats facing a large screen. Soft music began as they entered. The hall darkened and the screen lit up, showing the valley as it was before the work began. Forest mainly, a few farms scattered along the narrow bottoms.

What startled Henry was that they were above the valley, looking down as they seemed to drift through the air. So the old tales were right! The Old Ones could fly through the air! Here was proof of it.