"Curse him," repeated the sentry. "He bleeds them all white before they get this far! Very well, in with you. But look sharp you move in a hurry when this light turns white. If you're only half way over the line when the shield closes again, God help you!"

He laughed unpleasantly, pressed a button, and spoke into a diaphragm beside him. An instant later a light at the sentry box glowed white, and hurriedly the five slaves, straining, tugged their heavy cart into motion. They had barely succeeded in crossing the designated line when, with a sudden, crackling sound, a dust film rose from the ground behind them and the white light went out.

Gary, glancing back at Dr. Kang, saw the old man's forehead was beaded with perspiration. When he looked askance, Kang whispered, "They don't take many chances. They didn't leave the barrier open long. If we had been a minute slower in bringing the cart through—"

"What?" asked Nora Powell.

"The closing barrier would have smashed us into atoms. But we have learned one important thing, at any rate."

"Yes?" asked Gary.

"Again," said Dr. Kang, "as several times before, we have tangible evidence that the Magogean culture is not so high as they would believe. My people—" he said almost proudly—"have ways to open one portion of the force-shield at a time, admitting friends to its protection through a small opening. Theirs is a more elementary form. To open it in any spot is to open it everywhere. That may be a handy thing to know."

Thus entered Gary Lane and his companions into the city of Khundru. It was a strange city. Even Lark O'Day, who of them all was best capable to judge, having flung his madcap way afar amongst the planets of Sol's universe, admitted that.

"I've seen Greater New York," he said, "and Imperial Ceres. They're about tops in ultramodern culture. I've seen the barbaric splendors of the Venusian capital, and the filthy mud hovels the Mercurians call—or used to call—their temples. But never anywhere have I seen anything which looked like this."

And he shook his head bewilderedly at the heterogeneous architectural display sprawling about them. Khundru was a city of contradictions: the dwelling place of a people who believed themselves capable of attainments greater than they possessed.