“But you can’t—” he objected. I jabbed him in the ribs, once, in exactly the right place, and he subsided immediately.

“Okay, buddy,” he grunted. “Lay off. I’ll take you—but remember, it’s only because you forced me.” He wrinkled his brow in puzzlement. “But it’s beyond me why in blazes anyone would want to get to Callisto that bad—when we’d all give our left ears to get away.”

“It’s my business,” I said.

“Sure, sure,” he said placatingly, afraid of another poke. “Do whatever you damned please. But it’s your funeral—remember that.”

I smiled to myself, and watched the shining dome of Callisto City grow nearer. I was wondering what was going on beneath that peaceful-looking arc of plastine. It didn’t sound very good.

Finally we reached the city, and the truck edged carefully into the airlock. My helmet-window went foggy as the icy air of outside was replaced by the warm atmosphere of Callisto City, and then I saw my fellow truck-drivers climbing down and getting out of their spacesuits, in obvious relief at being able to shuck the bulky, uncomfortable things.

As I slid out of mine, I noticed one very strange thing. All the truck-drivers—every last one—wore curious golden collars around their necks. The collars were almost like dog-collars, thick, made of what looked like burnished bronze. They seemed oddly flexible and solid at the same time, and set in the middle of each was a little meter that kept clicking away, recording some kind of data.

I looked around. There were twenty or thirty Callistans near me, and they all wore the collar. And they all wore the same facial expression, too. The best way to describe it is to call it a beaten look. They were all beaten men, spiritless, frightened—of what?

The intense fluorescent lights from above glinted brightly off the collars. Was wearing them some kind of local custom, I wondered? Or a protection against something?