"They are new!" I cried. "They are too beautiful, too perfect to be ruthless. Perhaps they will be the friends of man."

But the lean Earthman's head shook slightly, and his jaw tensed white.

"No, Barihorn," he whispered. "They will be our most deadly enemies. For they are quicker than the others, and they can fly. See! They are scouting over the city, and leading the others to attack. They are in command."

His tired, blood-shot gray eyes looked at me briefly.

"Malgarth will never repeat your error, Barihorn. No robot has ever betrayed him. Subservience is built into them. Their radio-senses are always tuned to those above. And, machines that they are, they can only obey."

We drove the Barihorn nearer the city, which Jeron identified from his charts as Achnor, the first outpost of the human colonists in this sector of the Galaxy. The siege grew hotter beneath us. The metal horde pressed ceaselessly against the double wall. And a fleet of the red colossal ships of Malgarth, circling above rained the nine hills with bombs and struck with the lightning of destroying rays.

Valiantly, the citizens fought to defend their homes. Every bright pylon seemed converted into a fortress. Swarming men were building barricades from the debris of shattered towers. Blue rays lanced back at the attacking cruisers, and raked the valley beyond the walls.

"We shall land," whispered Kel Aran.

"If we do," warned Jeron, "we may not leave again."

"Take us down," said the Earthman. "This is the only city we have found surviving. It may be the last. If we are to find Verel anywhere, it must be here."