Lynne and Lao Mei-O'Connell and most of the rest of the citizens of Barkutburg listened attentively while Rolf told them the full story. The trouble, it seemed, was caused by the fact that the Earthmen had brought electricity back to Mars.
"These creatures were forced to discard their corporeal bodies to survive on a planet as dead as this one," he went on. "Their food is electricity and they'd been existing on a starvation diet for thousands of years, until we got here."
"It's strange they never tried space-travel," said Lynne.
"I don't believe their philosophy admitted to such a materialistic solution," Rolf replied. "They must have progressed like farb in the spiritual direction to be able to discard their bodies at all. Probably couldn't manage it both ways."
"That makes sense, Rolf." Lao nodded, looked at Rolf with an appeal she could not put into words.
He understood, told her, "Your Revere is going to be right as purt. I know what you must have thought when Lynne gave you the message she got about what we were doing to him. I tried to conceal it for that reason but this young lady is too farbly strong telepathically to shut her out. I'm sorry I had to make him suffer but he understood. And I wasn't going to damage him permanently.
"We—that is, some of Tony Willis' bright young men, have managed to improve the necro-recorder so that it is no longer destructive of the mind of the usee. They'd been working on it against time—and against just such a situation as arose recently, when we were finally able to get Revere off duty for a bit."
"Thanks." Lao Mei-O'Connell said the word gratefully.
"It's been rough on you," Rolf told her, "but nothing like as rough as if our little friends got control of all the telepaths."
"What did they feed on that made them strong?" Lynne asked.