in one of the cities. Over the following days the men see more signs of activity in the city and one day they see a collection of crates lying in a plaza. To keep a longer watch on the crates Nelson and Jim take their rocketship’s lifeboat to Deimos and set up the spare telescope some distance from their landing site. Jim goes back to the lifeboat to get the telescope’s other lens and when he doesn’t come back after some time Nelson goes to see what’s taking him so long. He finds that Jim has been murdered: someone bashed in the back of Jim’s helmet to let the air out of his spacesuit and then sabotaged the lifeboat and its radio. Trying to spot the murderers while at the same time evading them, Nelson crosses the surface of Deimos in long, gliding bounds, hoping, in some desperation, to find the killers’ spaceship and somehow take it. Feeling that he’s being followed, he hides in a small, narrow canyon and, believing he’s under active pursuit, goes to its dead end and takes refuge in a cave that ends at a door. He hides in a side tunnel and watches five humanoid aliens come to the door, open it, and pass through. A few minutes later he goes through the door, through the airlock beyond, and into a large alien base under the surface of Deimos. As he’s exploring the base he’s confronted by one of the three-fingered aliens, who introduces himself as Kunosh, the leader of the Deimosians. Hearing of Jim Worden’s murder, the timid Kunosh enlists Nelson’s help in ridding Deimos of certain bad men who, Kunosh assures Nelson, killed his friend. In the control room of the hollow moon Nelson knocks out the five aliens who he believes killed Jim, enabling Kunosh’s people to tie them up. Then he finds out that the five came from Phobos, where his father and three other men are at risk. In response to Nelson’s demand and the taunts of one of the Phobosians, Kunosh tells Nelson that his people, both Deimosians and Phobosians, are not Martians. These aliens had originated on a planet revolving around the star Vega, where they had evolved a perfect society with a perfect culture. They want nothing to do with alien cultures, which they regard as absolutely inferior to theirs. But then they learned that the