He's a small, unremarkable-looking male—nut brown skin, black hair, narrow eyes, wiry build—and he's wearing a totally unremarkable-looking kilt and vest; in fact the only remarkable thing about him is his sword. It isn't a dueling sword, it's a power-assisted microfilament wire, capable of slicing through diamond armor as if it isn't there. It's completely invisible except for the red tracking bead that glows at its tip, almost two meters from his right hand.

Too bad. I brace, squeeze the trigger for a fraction of a second, then let go and try to blink away the hideous purple afterimages. There's a tremendously loud thunderclap, a vile stench of ozone and burned meat, and my arms hurt. The sword handle goes skittering across the worn flagstones, and I hastily jump out of the way—I don't want to lose a foot by accident—then I glance about, relying on my peripheral vision to tell me if anyone else is around.

"Scum!" I hiss in the direction of Mr. Crispy. I feel curiously unmoved by what I've just done, although I wish the afterimages would go away faster—you're supposed to use a blaster with flash-suppression goggles, but I didn't have time to grab them. The blaster is a simple weapon, just a small T-gate linked (via another pair of T-gates acting as a valve) to an endpoint orbiting in the photosphere of a supergiant star. It's messy, it's short-range, it'll take out anything short of full battle armor, and because it's basically just a couple of wormholes tied together with superstring, it's impossible to jam. On the minus side my ears are ringing, I can already feel the skin on my face itching with fresh radiation burns, and I think I melted a couple of the crypts. It's considered bad form for duelists to use blasters—or indeed anything that isn't strictly hand-powered—which is probably why he wasn't expecting it.

"Never bring a knife to a gun fight," I tell Mr. Crispy as I turn away from him. His right arm thinks about it for a moment, then falls off.

The rest of my journey home is uneventful, but I'm shaking, and my teeth are chattering with the aftershock by the time I get there. I shut the door and tell it to fuse with the walls, then drop into the single chair that sits in the middle of my room when the bed isn't extended. Did he know I hadn't recorded a backup? Did he realize my older self wouldn't have erased all my defensive reflexes, or that I'd know where to get hold of a blaster in the Invisible Republic? I've no idea. What I do know is someone just tried to kill me by stealth and without witnesses or the usual after-duel resurrection, which suggests that they want me offline while they find and tinker with my backups. Which makes it attempted identity theft, a crime against the individual that most polities rate as several degrees worse than murder.

There's no avoiding it now. I'm going to have to take a backup—and then I'm going to have to seek sanctuary inside the Yourdon experiment. As an isolated polity, disconnected from the manifold while the research project runs, it should be about as safe as anywhere can be. Just as long as none of my stalkers are signed up for it . . .

TAKING a backup is very easy—it's dealing with the aftereffects that's hard.

You need to find an A-gate with backup capability (which just means that it has a booth big enough to hold a human body and isn't specifically configured for special applications, like a military gate). There's one in every rehab apartment, used for making copies of furnishings and preparing dinner as well as deconstructing folks right down to the atomic level, mapping them, and reassembling them again. To make a backup snapshot you just sit down in the thing and tell your netlink to back you up. It's not instantaneous (it works by brute-force nanoscale disassembly, not wormhole magic), but you won't notice the possibly disturbing sensation of being buried in blue factory goop, eaten, digitized, and put back together again because your netlink will switch you off as soon as it starts to upload your neural state vector into the gate's buffer.

I'm nervous about the time gap. I don't like the idea of being offline for any length of time while an unknown party is trying to hijack my identity. On the other hand, not to make a backup, complete with my current suspicions, would be foolhardy—if they succeed in nailing me, I want my next copy to know exactly what the score is. (And to know about Kay.) There really isn't any way around it, so I take precautions. Before I get into the booth, I use the A-gate to run up some innocuous items that can be combined to make a very nasty booby trap. After installing it, I take a deep breath and stand still for nearly a minute, facing the open door of the booth. Just to steady my nerves, you understand.

I get inside. "Back me up," I say. The booth extrudes a seat, and I sit down, then the door seals and flashes up a WORKING sign. I just have time to see blue milky liquid swirling in through the vents at floor level before everything goes gray and I feel extremely tired.

Now, about those aftereffects. What should happen is that after a blank period you wake up feeling fuzzy-headed and a bit moist. The door opens, and you go and shower off the gel residue left by the gate. You've lost maybe a thousand seconds, during which time a membrane studded with about a thousand trillion robotic disassembly heads the size of large protein molecules has chewed through you one nanometer at a time, stripping you down to molecular feedstock, recording your internal state vector, and putting a fresh copy back together behind it as it scans down the tank. But you don't notice it because you're brain-dead for the duration, and when the door to the A-gate reopens, you can just pick up your life where you left it before the backup. You naturally feel a bit vague when you come up again, but it's still you. Your body is—

Wrong.

I try to stand up too fast, and my knees both give way under me. I slump against the wall of the booth, feeling dizzy, and as I hit the wall I realize I'm too short . I'm still at the stage of feeling rather than thinking. The next thing I know I'm sitting down again and the booth is uncomfortably narrow because my hips are too wide and I'm too short in the trunk as well. There's something else, too. My arms feel—odd, not wrong, just different. I lift a hand and put it in my lap, and my thighs feel too big, and then there's something else. Oh , I realize, sliding my hand between my legs, I'm not male. No, I'm female . I raise my other hand, explore my chest. Female and orthohuman .

This in itself is no big deal. I've been a female orthohuman before; I'm not sure when or for how long, and it's not my favorite body plan, but I can live with it for the time being. What makes me freak and stand upagain, so suddenly I get black spots in my visual field and nearly fall over, is the corollary. Someone tampered with my backup! And then the double take: I am the backup. Somewhere a different version of me has died.

"Shit," I say aloud, leaning against the frosted door of the cubicle. My voice sounds oddly unfamiliar, an octave higher and warmer. "And more shit."

I can't stay in here forever, but whatever I'm going to find out when I open the door can't be good. Steeling myself against a growing sense of dread, I hit the door latch. It's about then that I realize I'm not wearing anything. That's no surprise—my manifold jacket was made from T-gates, and T-gates are one of the things that an A-gate can't fabricate—but my leggings have gone, too, and they were ordinary fabric. I've been well and truly hacked, I realize with a growing sense of dread. The door slides open, admitting a gust of air that feels chilly against my damp skin. I blink and glance around. It looks like my apartment, but there's a blank white tablet on the low desk beside the chair, the booby trap has gone, and the door is back in the wall. When I examine it I see that it's the wrong color, and the chair isn't the one I ran up on the apartment gate.