Poul Anderson 
Circus of Hells 
A Flandry Book

Ace Lieutenant Dominic Flandry was not a man easily swayed from his duty to the Empire; not, that is, until galactic vice king Leon Ammon offered him a million-credit bribe, a voluptuous woman called Djana, and a chance to explore a dark and treasure-laden moon.Yet within the desolate peaks and valleys of that strange world of ice and shadows, Flandry found more than he had bargained for. Supposedly barren, the planet swarmed with a hideous race of strange, inhuman creatures, infernally controlled by a deranged and brilliant computer brain. Each, like a piece in a bizarre and vicious chess game, was programmed to kill. And although Flandry did not know it — so was the woman he loved.