Double-Cross

Revolt was brewing on Venus, led by the descendant of the first Earthmen to land. Svan was the leader making the final plans—plotting them a bit too well.
The Officer of the Deck was pleased as he returned to the main lock. There was no reason why everything shouldn't have been functioning perfectly, of course, but he was pleased to have it confirmed, all the same. The Executive Officer was moodily smoking a cigarette in the open lock, staring out over the dank Venusian terrain at the native town. He turned.
Everything shipshape, I take it! he commented.
The OD nodded. I'll have a blank log if this keeps up, he said. Every man accounted for except the delegation, cargo stowed, drivers ready to lift as soon as they come back.
The Exec tossed away his cigarette. If they come back.
Is there any question?
The Exec shrugged. I don't know, Lowry, he said. This is a funny place. I don't trust the natives.
Lowry lifted his eyebrows. Oh? But after all, they're human beings, just like us—
Not any more. Four or five generations ago they were. Lord, they don't even look human any more. Those white, flabby skins—I don't like them.
Acclimation, Lowry said scientifically. They had to acclimate themselves to Venus's climate. They're friendly enough.
The Exec shrugged again. He stared at the wooden shacks that were the outskirts of the native city, dimly visible through the ever-present Venusian mist. The native guard of honor, posted a hundred yards from the Earth-ship, stood stolidly at attention with their old-fashioned proton-rifles slung over their backs. A few natives were gazing wonderingly at the great ship, but made no move to pass the line of guards.
Of course, Lowry said suddenly, there's a minority who are afraid of us. I was in town yesterday, and I talked with some of the natives. They think there will be hordes of immigrants from Earth, now that we know Venus is habitable. And there's some sort of a paltry underground group that is spreading the word that the immigrants will drive the native Venusians—the descendants of the first expedition, that is—right down into the mud. Well— he laughed— maybe they will. After all, the fittest survive. That's a basic law of—