I still had my revolver in my other hand, though. I brought it up, and, by touch, found Cassandra's face, probing the barrel roughly over it. Once, in my early days, I'd rammed a gun barrel into a thug's mouth; this time, I had other ideas. I got the barrel positioned directly over her left eye, and pressed down hard with it — a little poetic justice.

I said, “I bet if I shoot through your glass eye, aiming up a bit, I'll tear your artificial brain apart. You want to find out?”

She said nothing. I called back over my shoulder, “Pickover!” The name echoed down the corridor, but I had no idea whether he heard me. I turned my attention back to Cassandra — or whoever the hell this really was. I cocked the trigger. “As far as I'm concerned, Cassandra Wilkins is my client — but you're not her. Who are you?”

“I am Cassandra Wilkins,” said the voice.

“No, you're not,” I said. “You're a man — or, at least, you've got a man's mind.”

“I can prove I'm Cassandra Wilkins,” said the supine form. “My name is Cassandra Pauline Wilkins; my birth name is Collier. I was born in Sioux City, Iowa, on 30 October 2079. I immigrated to New Klondike in July 2102. My citizenship number is—”

“Facts. Figures.” I shook my head. “Anyone could find those things out.”

“But I know stuff no one else could possibly know. I know the name of my childhood pets; I know what I did to get thrown out of school when I was fifteen; I know precisely where the original me had a tattoo; I…”

She went on, but I stopped listening.

Jesus Christ, it was almost the perfect crime. No one could really get away with stealing somebody else's identity — not for long. The lack of intimate knowledge of how the original spoke, of private things the original knew, would soon enough give you away, unless—

Unless you were the spouse of the person whose identity you'd appropriated.

“You're not Cassandra Wilkins,” I said. “You're Joshua Wilkins. You took her body; you transferred into it, and she transferred—” I felt my stomach tighten; it really was a nearly perfect crime. “And she transferred nowhere ; when the original was euthanized, she died. And that makes you guilty of murder.”

“You can't prove that,” said the female voice. “No biometrics, no DNA, no fingerprints. I'm whoever I say I am.”

“You and Cassandra hatched this scheme together,” I said. “You both figured Pickover had to know where the alpha deposit was. But then you decided that you didn't want to share the wealth with anyone — not even your wife. And so you got rid of her, and made good your escape at the same time.”

“That's crazy,” the female voice said. “I hired you. Why on — on Mars — would I do that, then?”

“You expected to the police to come out to investigate your missing-person report; they were supposed to find the body in the basement of NewYou. But they didn't, and you knew suspicion would fall on you — the supposed spouse! — if you were the one who found it. So you hired me — the dutiful wife, worried about her poor, missing hubby! All you wanted was for me to find the body.”

“Words,” said Joshua. “Just words.”

“Maybe so,” I said. “I don't have to satisfy anyone else. Just me. I will give you one chance, though. See, I want to get out of here alive — and I don't see any way to do that if I leave you alive, too. Do you? If you've got an answer, tell me — otherwise, I've got no choice but to pull this trigger.”

“I promise I'll let you go,” said Joshua.

I laughed, and the sound echoed in the corridor. “You promise? Well, I'm sure I can take that to the bank.”

“No, seriously,” said Joshua. “I won't tell anyone. I—”

“Are you Joshua Wilkins?” I asked.

Silence.

“Are you?”

I felt the face moving up and down a bit, the barrel of my gun shifting slightly in the eye socket as it did so. “Yes.”

“Well, rest in peace,” I said, and then, with relish, added, Josh.”

I pulled the trigger.

The flash from the gun barrel briefly lit up the female, freckled face, which was showing almost human horror. The revolver snapped back in my hand, then everything was dark again. I had no idea how much damage the bullet would do to the brain. Of course, the artificial chest wasn't rising and falling, but it never had been. And there was nowhere to check for a pulse. I decided I'd better try another shot, just to be sure. I shifted slightly, thinking I'd put this one through the other eye, and—

And Joshua's arms burst up, pushing me off him. I felt myself go airborne, and was aware of Joshua scrambling to his feet. He scooped up the flashlight, and as he swung it and himself around, it briefly illuminated his face. There was a deep pit where one eye used to be.

I started to bring the gun up and—

And Joshua thumbed off the flashlight. The only illumination was a tiny bit of light, far, far down the corridor, spilling out from the torture room; it wasn't enough to let me see Joshua clearly. But I squeezed the trigger, and heard a bullet ricochet — either off some part of Joshua's metal internal skeleton, or off the corridor wall.

I was the kind of guy who always knew exactly how many bullets he had left: two. I wasn't sure I wanted to fire them both off blindly, but—

I could hear Joshua moving closer. I fired again. This time, the feminine voice box made a sound between an oomph and the word “ouch,” so I knew I'd hit him.

One bullet to go.

I started walking backward — which was no worse than walking forward; I was just as likely to trip either way in this near-total darkness. The body in the shape of Cassandra Wilkins was much smaller than mine — but also, although it shamed the macho me to admit it, much stronger. It could probably grab me by the shoulders and pound my head up into the ceiling, just as I'd pounded hers — and I rather suspect mine wouldn't survive. And if I let it get hold of my arm, it could probably wrench the gun from me; five bullets hadn't been enough to stop the artificial body, but one was all it would take to ice me for good.

And so I decided it was better to have an empty gun than a gun that could potentially be turned on me. I held the weapon out in front, took my best guess, and squeezed the trigger one last time.

The revolver barked, and the flare from the muzzle lit the scene, stinging my eyes. The artificial form cried out — I'd hit a spot its sensors felt was worth protecting with a major pain response, I guess. But the being kept moving forward. Part of me thought about turning tail and running — I still had the longer legs, even if I couldn't move them as fast — but another part of me couldn't bring myself to do that. The gun was of no more use, so I threw it aside. It hit the corridor wall, making a banging sound, then fell to the deck plates, producing more clanging as it bounced against them.

Of course, as soon as I'd thrown the gun away, I realized I'd made a mistake. I knew how many bullets I'd shot, and how many the gun held, but Joshua probably didn't; even an empty gun could be a deterrent if the other person thought it was loaded.

We were facing each other — but that was all that was certain. Precisely how much distance there was between us I couldn't say. Although running produced loud, echoing footfalls, either of us could have moved a step or two forward or back — or left or right — without the other being aware of it. I was trying not to make any noise, and a transfer could stand perfectly still, and be absolutely quiet, for hours on end.

I had no idea how badly I'd hurt him. In fact, given that he'd played possum once before, it was possible the sounds of pain were faked, just to make me think he was damaged. My great grandfather said clocks used to make a ticking sound with the passing of each second; I'd never heard such a thing, but I was certainly conscious of time passing in increments as we stood there, each waiting for the other to make a move.