The blind spot yawns , baring sharp ivory fangs. Amber shakes her head, dismissing the momentary hallucination. "Lemme guess. You woke up in a room, and this alien ghost tells you the human species is extinct and asks you to do a number on me. Is that right?"

Amber nods, as an icy finger of fear trails up and down her spine. "Is it lying?" she asks.

"Damn right." The blind spot is smiling, now, and the smile on the void won't go away – she can see the smile, just not the body it's attached to. "My reckoning is, we're about sixteen light-years from Earth. The Wunch came through here, stripped the dump, then took off for parts unknown; it's a trashhole, you wouldn't believe it. The main life-form is an incredibly ornate corporate ecosphere, legal instruments breeding and replicating. They mug passing sapients and use them as currency."

There's a triangular, pointy head behind the smile, slit eyes and sharp ears, a predatory, intelligent-looking but infinitely alien face. Amber can see it out of the corners of her eyes when she looks around the piazza. "You mean we, uh, they grabbed us when we appeared, and they've mangled my memories —" Amber suddenly finds it incredibly difficult to concentrate, but if she focuses on the smile, she can almost see the body behind it, hunched like a furry chicken, tail wrapped neatly around its front paws.

"Yeah. Except they didn't bargain on meeting something like me." The smile is infinitely wide, a Cheshire-cat grin on front of an orange-and-brown stripy body that shimmers in front of Amber's gaze like a hallucination. "Your mother's cracking tools are self-extending, Amber. Do you remember Hong Kong?"

"Hong —"

There is a moment of painless pressure, then Amber feels huge invisible barriers sliding away on all sides. She looks around, for the first time seeing the piazza as it really is, half the crew of the Field Circus waiting nervously around her, the grinning cat crouched on the floor at her feet, the enormous walls of recomplicating data that fence their little town off from the gaping holes – interfaces to the other routers in the network.

"Welcome back," Pierre says gravely, as Amber gives a squeak of surprise and leans forward to pick up her cat. "Now you're out from under, how about we start trying to figure out how to get home?"

Welcome to decade the sixth, millennium three. These old datelines don't mean so much anymore, for while some billions of fleshbody humans are still infected with viral memes, the significance of theocentric dating has been dealt a body blow. This may be the fifties, but what that means to you depends on how fast your reality rate runs. The various upload clades exploding across the reaches of the solar system vary by several orders of magnitude – some are barely out of 2049, while others are exploring the subjective thousandth millennium.

While the Field Circus floats in orbit around an alien router (itself orbiting the brown dwarf Hyundai +4904 /–56 ), while Amber and her crew are trapped on the far side of a wormhole linking the router to a network of incomprehensibly vast alien mindscapes – while all this is going on, the damnfool human species has finally succeeded in making itself obsolete. The proximate cause of its displacement from the pinnacle of creation (or the pinnacle of teleological self-congratulation, depending on your stance on evolutionary biology) is an attack of self-aware corporations. The phrase "smart money" has taken on a whole new meaning, for the collision between international business law and neurocomputing technology has given rise to a whole new family of species – fast-moving corporate carnivores in the Net. The planet Mercury has been broken up by a consortium of energy brokers, and Venus is an expanding debris cloud, energized to a violent glare by the trapped and channeled solar output. A million billion fist-sized computing caltrops, backsides glowing dull red with the efflux from their thinking, orbit the sun at various inclinations no farther out than Mercury used to be.

Billions of fleshbody humans refuse to have anything to do with the blasphemous new realities. Many of their leaders denounce the uploads and AIs as soulless machines. Many more are timid, harboring self-preservation memes that amplify a previously healthy aversion to having one's brain peeled like an onion by mind-mapping robots into an all-pervading neurosis. Sales of electrified tinfoil-lined hats are at an all-time high. Still, hundreds of millions have already traded their meat puppets for mind machines, and they breed fast. In another few years, the fleshbody populace will be an absolute minority of the posthuman clade. Sometime later, there will probably be a war. The dwellers in the thoughtcloud are hungry for dumb matter to convert, and the fleshbodies make notoriously poor use of the collection of silicon and rare elements that pool at the bottom of the gravity well that is Earth.

Energy and thought are driving a phase-change in the condensed matter substance of the solar system. The MIPS per kilogram metric is on the steep upward leg of a sigmoid curve – dumb matter is coming to life as the mind children restructure everything with voracious nanomechanical servants. The thoughtcloud forming in orbit around the sun will ultimately be the graveyard of a biological ecology, another marker in space visible to the telescopes of any new iron-age species with the insight to understand what they're seeing: the death throes of dumb matter, the birth of a habitable reality vaster than a galaxy and far speedier. Death throes that, within a few centuries, will mean the extinction of biological life within a light-year or so of that star – for the majestic Matrioshka brains, though they are the pinnacles of sentient civilization, are intrinsically hostile environments for fleshy life.

Pierre, Donna-the-all-seeing-eye, and Su Ang fill Amber in on what they've discovered about the bazaar – as they call the space the ghost referred to as the demilitarized zone – over ice-cold margaritas and a very good simulation of a sociable joint. Some of them have been on the loose in here for subjective years. There's a lot of information to absorb.

"The physical layer is half a light-hour in diameter, four hundred times as massive as Earth," Pierre explains. "Not solid, of course – the largest component is about the size my fist used to be." Amber squints, trying to remember how big that was – scale factors are hard to remember accurately. "I met this old chatbot that said it's outlived its original star, but I'm not sure it's running with a full deck. Anyway, if it's telling the truth, we're a third of a light year out from a closely coupled binary system – they use orbital lasers the size of Jupiter to power it without getting too close to all those icky gravity wells."

Amber is intimidated, despite her better judgment, because this bizarre bazaar is several hundred billion times as big as the totality of human presingularity civilization. She tries not to show it in front of the others, but she's worried that getting home may be impossible – requiring enterprise beyond the economic event horizon, as realistic a proposition as a dime debuting as a dollar bill. Still, she's got to at least try. Just knowing about the existence of the bazaar will change so many things …

"How much money can we lay our hands on?" She asks. "What is money hereabouts, anyway? Assuming they've got a scarcity-mediated economy. Bandwidth, maybe?"

"Ah, well." Pierre looks at her oddly. "That's the problem. Didn't the ghost tell you?"

"Tell me?" Amber raises an eyebrow. "Yeah, but it hasn't exactly proven to be a reliable guide to anything, has it?"

"Tell her," Su Ang says quietly. She looks away, embarrassed by something.