At the top of the staircase, Sadeq comes to a door of aged wood bound in iron. It doesn't belong here: It's a cultural and architectural anomaly. The handle is a loop of black metal. Sadeq regards it as if it's the head of an asp, poised to sting. Nevertheless, he reaches out and turns the handle, steps across the threshold into a palace out of fantasy.

None of this is real , he reminds himself. It's no more real than an illusion conjured by one of the jinni of the thousand nights and one night. Nevertheless, he can't save himself from smiling at the scene – a sardonic smile of self-deprecating humor, tempered by frustration.

Sadeq's captors have stolen his soul and locked it – him – in a very strange prison, a temple with a tower that rises all the way to Paradise. It's the whole classical litany of medievalist desires, distilled from fifteen hundred years of literature. Colonnaded courtyards, cool pools lined with rich mosaics, rooms filled with every imaginable dumb matter luxury, endless banquets awaiting his appetite – and dozens of beautiful un-women, eager to fulfill his every fantasy. Sadeq, being human, has fantasies by the dozen, but he doesn't dare permit himself to succumb to temptation. I'm not dead , he reasons. Therefore, how can I be in Paradise? Therefore, this must be a false paradise, a temptation sent to lead me astray. Probably. Unless I am dead, because Allah, peace be unto him, considers a human soul separated from its body to be dead. But if that's so, isn't uploading a sin? In which case, this can't be Paradise because I am a sinner. Besides which, this whole setup is so puerile!

Sadeq has always been inclined to philosophical inquiry, and his vision of the afterlife is more cerebral than most, involving ideas as questionable within the framework of Islam as those of Teilhard de Chardin were to the twentieth-century Catholic church. If there's one key indicator of a false paradise in his eschatology, it's two-and-seventy brainlessly beautiful houris waiting to do his bidding. So it follows that he can't really be dead …

The whole question of reality is so vexing that Sadeq does what he does every night. He strides heedlessly across priceless works of art, barging hastily through courtyards and passageways, ignoring niches in which nearly naked supermodels lie with their legs apart, climbing stairs – until he comes to a small unfurnished room with a single high window in one wall. There he sits on the floor, legs crossed, meditating; not in prayer, but in a more tightly focused ratiocination. Every false night (for there is no way to know how fast time is passing, outside this cyberspace pocket), Sadeq sits and thinks , grappling with Descartes's demon in the solitude of his own mind. And the question he asks himself every night is the same: Can I tell if this is the true hell? And if it is not, how can I escape?

The ghost tells Amber that she has been dead for just under a third of a million years. She has been reinstantiated from storage – and has died again – many times in the intervening period, but she has no memory of this; she is a fork from the main bough, and the other branches expired in lonely isolation.

The business of resurrection does not, in and of itself, distress Amber unduly. Born in the post-Moravec era, she merely finds some aspects of the ghost's description dissatisfyingly incomplete. It's like saying she was drugged and brought hither without stating whether by plane, train, or automobile.

She doesn't have a problem with the ghost's assertion that she is nowhere near Earth – indeed, that she is approximately eighty thousand light-years away. When she and the others took the risk of uploading themselves through the router they found in orbit around Hyundai +4904 /–56 they'd understood that they could end up anywhere or nowhere. But the idea that she's still within the light cone of her departure strikes her as dubious. The original SETI broadcast strongly implied that the router is part of a network of self-replicating instantaneous communicators, spawning and spreading between the cold brown dwarf stars that litter the galaxy. She'd somehow expected to be much farther from home by now.

Somewhat more disturbing is the ghost's assertion that the human genotype has rendered itself extinct at least twice, that its home planet is unknown, and that Amber is nearly the only human left in the public archives. At this point, she interrupts. "I hardly see what this has to do with me!" Then she blows across her coffee glass, trying to cool the contents. "I'm dead," she explains, with an undertone of knowing sarcasm in her voice. "Remember? I just got here. A thousand seconds ago, subjective time, I was in the control node of a starship, discussing what to do with the router we were in orbit around. We agreed to send ourselves through it, as a trade mission. Then I woke up in bed here in the umpty-zillionth century, wherever and whatever here is. Without access to any reality ackles or augmentation, I can't even tell whether this is real or an embedded simulation. You're going to have to explain why you need an old version of me before I can make sense of my situation – and I can tell you, I'm not going to help you until I know who you are. And speaking of that, what about the others? Where are they? I wasn't the only one, you know?"

The ghost freezes in place for a moment, and Amber feels a watery rush of terror: Have I gone too far ? she wonders.

"There has been an unfortunate accident," the ghost announces portentously. It morphs from a translucent copy of Amber's own body into the outline of a human skeleton, elaborate bony extensions simulating an osteosarcoma of more-than-lethal proportions. "Consensus-we believe that you are best positioned to remediate the situation. This applies within the demilitarized zone."

"Demilitarized?" Amber shakes her head, pauses to sip her coffee. "What do you mean? What is this place?"

The ghost flickers again, adopting an abstract rotating hypercube as its avatar. "This space we occupy is a manifold adjacent to the demilitarized zone. The demilitarized zone is a space outside our core reality, itself exposed to entities that cross freely through our firewall, journeying to and from the network outside. We-us use the DMZ to establish the informational value of migrant entities, sapient currency units and the like. We-us banked you upon arrival against future options trades in human species futures."

"Currency!" Amber doesn't know whether to be amused or horrified – both reactions seem appropriate. "Is that how you treat all your visitors?"

The ghost ignores her question. "There is a runaway semiotic excursion under way in the zone. We-us believe only you can fix it. If you agree to do, so we will exchange value, pay, reward cooperation, expedite remuneration, manumit, repatriate."

Amber drains her coffee cup. "Have you ever entered into economic interactions with me, or humans like me, before?" she asks. "If not, why should I trust you? If so, why have you revived me? Are there any more experienced instances of myself running around here?" She raises a skeptical eyebrow at the ghost. "This looks like the start of an abusive relationship."

The ghost continues to sidestep her attempts to work out where she stands. It flickers into transparency, grows into a hazy window on a landscape of impossible shapes. Clouds sprouting trees drift above a landscape of green, egg-curved hills and cheesecake castles. "Nature of excursion: alien intelligence is loose in the DMZ," it asserts. "Alien is applying invalid semiotics to complex structures designed to sustain trade. You know this alien, Amber. We require solution. Slay the monster, we will give you line of credit. Your own reality to control, insight into trade arrangements, augmented senses, ability to travel. Can even upgrade you to you-we consensus, if desired."