Halsey smiled grimly. “What he means, Haljan, is that things are not always what they seem these days. One cannot always tell a friend from an enemy. The Planetara is a public vessel. You have––how many is it, Carter?––thirty or forty passengers this trip to-night?”

“Thirty-eight,” said Carter.

“There are thirty-eight people listed for the flight to Ferrok-Shahn to-night,” Halsey said slowly. “And some may not be what they seem.” He raised his thin dark hand. “We have information––” He paused. “I confess, we know almost nothing––hardly more than enough to alarm us.”

Captain Carter interjected, “I want you and Dean to be on your guard. Once on the Planetara it is difficult for us to talk openly, but be watchful. I will arrange for us to be doubly armed.”

Vague, perturbing words! Halsey said, “They tell me George Prince is listed for the voyage. I am suggesting, 311 Haljan, that you keep your eye especially upon him. Your duties on the Planetara leave you comparatively free, don’t they?”

“Yes,” I agreed. With the first and second officers on duty, and the captain aboard, my routine was more or less that of an understudy.

I said, “George Prince! Who is he?”

“A mechanical engineer,” said Halsey. “An under-official of the Earth Federated Radium Corporation. But he associates with bad companions––particularly Martians.”

I had never heard of this George Prince, though I was familiar with the Federated Radium Corporation, of course. A semi-government trust, which controlled virtually the entire Earth supply of radium.