The Mystery of Deneb IV by Robert Silverberg - When Dave Carter tried to rescue the Denebians he found himself in a den of thieves. And he had cause to remember Shakespeare's observation: "He who steals my purse steals trash."
The first thing that crossed Dave Carter's mind was that the SOS was some kind of hoax. Then a fist thudded into the back of his neck, and he knew it was worse than a hoax—it was a trap.
His knees sagged and he grabbed wildly for the side of his spaceship. Steadying himself, he struck out with a fist.
His unknown assailant grunted. Carter's eyes widened as he discovered he was fighting another Earthman, here on this alien world in the Deneb system. What the devil is this? Carter asked himself, as his fist crashed into the other's stomach. They ask me to come rescue them—and then they jump me from behind.
The man was wearing the gray-and-gold uniform of the missing Vanguard expedition. He was a big, rangy spaceman. His eyes glittered with a cold menace that Carter had never seen in human eyes before.
Carter reached back, grasped the rungs of the ladder behind him with both hands, and kicked out at the other. The man crumpled backward onto the ground. Carter ran over to him.
He put a knee on the other's chest. "Who are you?" he demanded.
No answer.
