The Directory-ship Tethys made the first landing on the planet, L21612. It was a goodly world, with an ample atmosphere and many seas, which the nearby sun warmed so lavishly that a perpetual cloud-bank hid them and all the solid ground from view. It had mountains and islands and high plateaus. It had day and night and rain. It had an equable climate, rather on the tropical side. But it possessed no life...
The problem of separating the friends from the enemies was a major one in the conquest of space as many a dead spacer could have testified. A tough job when you could see an alien and judge appearances; far tougher when they were only whispers on the wind.
It began when a pedestrian got hit by a cab in New York City. No doubt it was the only motor mishap in the history of creation that reached out among the stars--for far out in space a signal was registered: Something has gone wrong....for the doctors discovered their accident patient had two hearts. It was the beginning of the discovery that the Earth had been invaded by 10 such creatures from Outer Space.
A man can be killed by a toy gun--he can die of fright, for heart attacks can kill. What, then, is the deadly thing that must be sealed away, forever locked in buried concrete--a thing or an idea?
Benson did his best to keep his colony from going native, but what can you do when the Natives have a rare human intelligence and know all about the facts of life?