"The heathen geeks, they wear no breeks," the Terrans sang. But on a crazy world like Ullr, clothes didn't make the fighting man. There both red and yellow meant danger--and blood!

* * * * * I

The big armor-tender vibrated, gently and not unpleasantly, as the contragravity field alternated on and off. Sometimes it rocked slightly, like a boat on the water, and, in the big screen which served in lieu of a window at the front of the control-cabin, the dingy-yellow landscape would seem to tilt a little. The air was faintly yellow, the sky was yellow with a greenish cast, and the clouds were green-gray.

No human had ever set foot on the surface, or breathed the air, of Niflheim. To have done so would have been instant death; the air was a mixture of free fluorine and fluoride gasses, the soil was metallic fluorides, damp with acid rains, and the river was pure hydrofluoric acid. Even the ordinary spacesuit would have been no protection; the glass and rubber and plastic would have disintegrated in a matter of minutes. People came to Niflheim, and worked the mines and uranium refineries and chemical plants, but they did so inside power-driven and contragravity-lifted armor, and they lived on artificial satellites two thousand miles off-planet. Niflheim was worse than airless; much worse.

The chief engineer sat at his controls, making the minor lateral adjustments in the vehicle's position which were not possible to the automatic controls. At his own panel of instruments, a small man with grizzled black hair around a bald crown, and a grizzled beard, chewed nervously at the stump of a dead cigar and listened intently. A large, plump-faced, young man in soiled khaki shirt and shorts, with extremely hairy legs, was doodling on his notepad and eating candy out of a bag. And a black-haired girl in a suit of coveralls three sizes too big for her, and, apparently, not much of anything else, lounged with one knee hooked over her chair-arm, staring into the screen at the distant horizon.

"I can see them," the girl said, lifting a hand in front of her. "At two o'clock, about one of my hand's-breaths above the horizon. But only four of them."

The man with the grizzled beard put his face into the fur around the eyepiece of the telescopic-'visor and twisted a dial. "You have good eyes, Miss Quinton," he complimented. "The fifth's inside the handling machine. One of the Ullrans. Gorkrink."

* * * * *

The largest of the specks that had appeared on the horizon resolved itself into a handling-machine, a thing like an oversized contragravity-tank, with a bull-dozer-blade, a stubby derrick-boom instead of a gun, and jointed, claw-tipped, arms at the sides. The smaller dots grew into personal armor--egg-shaped things that sprouted arms and grab-hooks and pushers in all directions. The man with the grizzled beard began talking rapidly into his hand-phone, then hung it up.