"You're an astro-engineer, Mr. Murdock. We're interested." "Who's 'we'?" The middle-aged man pulled out a handkerchief with which to pat his sallow cheeks. "I'm sorry, Mr. Murdock, but I'm not at liberty to reveal that." Gavin scowled. "Who are you?" "One alias is as good as another." The man smiled pleasantly. "X will do for the present. Suppose you call me Mr. X. I represent a group, Mr. Murdock, who are interested in the Nova's space drive." "Well?" said Gavin dryly. The group whom Mr. X represented weren't the only ones interested in Nova's spacedrive. The T.I.S., for one, was particularly concerned about it. The Nova made the crossing between Jupiter and Venus with her contraband load of slaves in an impossibly short space of time. The crack patrol ships of the Empire had neither been able to keep the Nova in sight nor trap her. Gavin's early experience as an astro-engineer with Tri-World had been the really important reason that he had been assigned to the job. Mr. X put the tips of his pudgy fingers together. "As third assistant-engineer of the Nova, Mr. Murdock, you will have an unrivaled opportunity to study her drive. We're willing to pay and pay handsomely for the secret of that drive." "How much?" "A million credits," replied Mr. X, without blinking an eye. Gavin allowed his breath to escape between his teeth. He knew now who was behind Mr. X and it didn't make him any happier. Only one of the big corporations on Terra-United Spaceways, General Atomic, Tri-World, or Amalgamated plastic—could offer such a sum. The Gargantuan companies maintained their own investigation agencies, ruthless, efficient gestapos willing to go to any length to get their hands on valuable discoveries. He stood up, saying, "I'll think it over." "I'm afraid you'll have to reach a decision now." X's voice was cold. Gavin's hard blue eyes went wary. The T.I.S. maintained in their secret files a complete record of every man and woman engaged in the slave trade. Gavin had studied it thoroughly in preparation for this assignment. Trev, he knew, besides being a broker in slaves for Josiah Cabot, was suspected of dealing in merchandise of a great deal more dangerous character. Scientific secrets. Trev was a free lance, buying from independent spies and selling to the highest bidder. He was tolerated because the very corporations and governments he stole from were also his patrons. Trev would have connections with all the secret agencies of the different corporations. If anyone were dickering with X to sell the Nova's space drive, Trev would be the likeliest suspect. And, if Trev thought Gavin was dickering with X, the Martian wouldn't hesitate to betray him to Cabot. That was one side. On the other hand, it might be a trap. His best policy was to have nothing to do with X. He said, "I don't do business with someone I don't know. I'm going now. Don't try to stop me." "Meg," said Mr. X.