“Well, I’ll tell you.” Donovan rolled onto his stomach, and took a firm grip on his wild, red hair to hold his head up. “There’s a certain principle involved. After all, as a trouble shooter, I’ve played a part in the development of new robots. There’s the principle of aiding scientific advance. But don’t get me wrong. It’s not the principle that keeps me going; it’s the money they pay us. Greg!”

Powell jumped at Donovan’s wild shout, and his eyes followed the redhead’s to the visiplate, when they goggled in fixed horror. He whispered, “Holy—howling—Jupiter!”

Donovan scrambled breathlessly to his feet, “Look at them, Greg. They’ve gone nuts.”

Powell said, “Get a pair of suits. We’re going out there.”

He watched the posturings of the robots on the visiplate. They were bronzy gleams of smooth motion against the shadowy crags of the airless asteroid. There was a marching formation now, and in their own dim body light, the rough-hewn walls of the mine tunnel swam past noiselessly, checkered with misty erratic blobs of shadow. They marched in unison, seven of them, with Dave at the head. They wheeled and turned in macabre simultaneity; and melted through changes of formation with the weird ease of chorus dancers in Lunar Bowl.

Donovan was back with the suits, “They’ve gone jingo on us, Greg. That’s a military march.”

“For all you know,” was the cold response, “it may be a series of calisthenic exercises. Or Dave may be under the hallucination of being a dancing master. Just you think first, and don’t bother to speak afterward, either.”

Donovan scowled and slipped a detonator into the empty side holster with an ostentatious shove. He said, “Anyway, there you are. So we work with new-model robots. It’s our job, granted. But answer me one question. Why… why does something invariably go wrong with them?”

“Because,” said Powell, somberly, “we are accursed. Let’s go!”

Far ahead through the thick velvety blackness of the corridors that reached past the illuminated circles of their flashlights, robot light twinkled.

“There they are,” breathed Donovan.

Powell whispered tensely, “I’ve been trying to get him by radio but he doesn’t answer. The radio circuit is probably out.”

“Then I’m glad the designers haven’t worked out robots who can work in total darkness yet. I’d hate to have to find seven mad robots in a black pit without radio communication, if they weren’t lit up like blasted radioactive Christmas trees.”

“Crawl up on the ledge above, Mike. They’re coming this way, and I want to watch them at close range. Can you make it?”

Donovan made the jump with a grunt. Gravity was considerably below Earth-normal, but with a heavy suit, the advantage was not too great, and the ledge meant a near ten-foot jump. Powell followed.

The column of robots was trailing Dave single-file. In mechanical rhythm, they converted to double and returned to single in different order. It was repeated over and over again and Dave never turned his head.