* Manfred – fifty, with the fashionably pale complexion of the digerati, healthy-looking for his age, standing beside a transmigration bush with a stupid grin on his face. He's decided to take the final step, not simply to spawn external mental processes running in an exocortex of distributed processors, but to move his entire persona right out of meatspace, into wherever it is that the uploads aboard the Field Circus have gone. Annette, skinny, elegant, and very Parisian, stands beside him, looking as uncertain as the wife of a condemned man.

* A wedding, shi'ite, Mut'ah – of limited duration. It's scandalous to many, but the mamtu'ah isn't moslem, she wears a crown instead of a veil, and her groom is already spoken of in outraged terms by most other members of the trans-Martian Islamic clergy. Besides which, in addition to being in love, the happy couple have more strategic firepower than a late-twentieth-century superpower. Their cat, curled at their feet, looks smug: She's the custodian of the permissive action locks on the big lasers.

* A speck of ruby light against the darkness – red-shifted almost into the infrared, it's the return signal from the Field Circus's light sail as the starwhisp passes the one-light-year mark, almost twelve trillion kilometers out beyond Pluto. (Although how can you call it a starwhisp when it masses almost a hundred kilograms, including propulsion module? Starwhisps are meant to be tiny!)

* Collapse of the trans-Lunar economy: Deep in the hot thinking depths of the solar system, vast new intellects come up with a new theory of wealth that optimizes resource allocation better than the previously pervasive Free Market 1.0. With no local minima to hamper them, and no need to spawn and reap start-ups Darwin-style, the companies, group minds, and organizations that adopt the so-called Accelerated Salesman Infrastructure of Economics 2.0 trade optimally with each other. The phase change accelerates as more and more entities join in, leveraging network externalities to overtake the traditional ecosystem. Amber and Sadeq are late on the train, Sadeq obsessing about how to reconcile ASI with murabaha and mudaraba while the postmodern economy of the mid-twenty-first century disintegrates around them. Being late has punitive consequences – the Ring Imperium has always been a net importer of brainpower and a net exporter of gravitational potential energy. Now it's a tired backwater, the bit rate from the red-shifted relativisitic probe insufficiently delightful to obsess the daemons of industrial routing. In other words, they're poor.

* A message from beyond the grave: The travelers aboard the starship have reached their destination, an alien artifact drifting in chilly orbit around a frozen brown dwarf. Recklessly they upload themselves into it, locking the starwhisp down for years of sleep. Amber and her husband have few funds with which to pay for the propulsion lasers: what they have left of the kinetic energy of the Ring Imperium – based on the orbital momentum of a small Jovian inner moon – is being sapped, fast, at a near-loss, by the crude requirements of the exobionts and metanthropes who fork and spawn in the datasphere of the outer Jovians. The cost of importing brains to the Ring Imperium is steep: In near-despair Amber and Sadeq produce a child, Generation 3.0, to populate their dwindling kingdom. Picture the cat, offended, lashing its tail beside the zero-gee crib.

* Surprise and postcards from the inner orbitals – Amber's mother offers to help. For the sake of the child, Sadeq offers bandwidth and user interface enrichment. The child forks, numerous times, as Amber despairingly plays with probabilities, simulating upbringing outcomes. Neither she nor Sadeq are good parents – the father absent-minded and prone to lose himself in the intertextual deconstruction of surahs, the mother ragged-edged from running the economy of a small and failing kingdom. In the space of a decade, Sirhan lives a dozen lives, discarding identities like old clothes. The uncertainty of life in the decaying Ring Imperium does not entrance him, his parents' obsessions annoy him, and when his grandmother offers to fund his delta vee and subsequent education in one of the orbitals around Titan, his parents give their reluctant assent.

* Amber and Sadeq separate acrimoniously. Sadeq, studies abandoned in the face of increasing intrusions from the world of what is into the universe of what should be, joins a spacelike sect of sufis, encysted in a matrix of vitrification nanomechs out in the Oort cloud to await a better epoch. His instrument of will – the legal mechanism of his resurrection – specifies that he is waiting for the return of the hidden, twelfth imam.

* For her part, Amber searches the inner system briefly for word of her father – but there's nothing. Isolated and alone, pursued by accusing debts, she flings herself into a reborganization, stripping away those aspects of her personality that have brought her low; in law, her liability is tied to her identity. Eventually she donates herself to a commune of also-rans, accepting their personality in return for a total break with the past.

* Without Queen and consort, the Ring Imperium – now unmanned, leaking breathing gases, running on autonomic control – slowly deorbits into the Jovian murk, beaming power to the outer moons until it punches a hole in the cloud deck in a final incandescent smear of light, the like of which has not been seen since the Shoemaker-Levy 9 impact.

* Sirhan, engrossed in Saturnalia, is offended by his parents' failure to make more of themselves. And he resolves to do it for them, if not necessarily in a manner of their liking.

"You see, I am hoping you will help me with my history project," says the serious-faced young man.

"History project." Pierre follows him along the curving gallery, hands clasped behind his back self-consciously to keep from showing his agitation: "What history is this?"

"The history of the twenty-first century," says Sirhan. "You remember it, don't you?"

"Remember it —" Pierre pauses. "You're serious?"

"Yes." Sirhan opens a side door. "This way, please. I'll explain."

The door opens onto what used to be one of the side galleries of the museum building, full of interactive exhibits designed to explain elementary optics to hyperactive children and their indulgent parental units. Traditional optics are long since obsolete – tunable matter can slow photons to a stop, teleport them here to there, play ping-pong with spin and polarization – and besides, the dumb matter in the walls and floor has been replaced by low-power computronium, heat sinks dangling far below the floor of the lily-pad habitat to dispose of the scanty waste photons from reversible computation. Now the room is empty.

"Since I became curator here, I've turned the museum's structural supports into a dedicated high-density memory store. One of the fringe benefits of a supervisory post, of course. I have about a billion avabits of capacity, enough to archive the combined sensory bandwidth and memories of the entire population of twentieth-century Earth – if that was what interested me."

Slowly the walls and ceiling are coming to life, brightening, providing a dizzyingly vibrant view of dawn over the rim wall of Meteor Crater, Arizona – or maybe it's downtown Baghdad.

"Once I realized how my mother had squandered the family fortune, I spent some time looking for a solution to the problem," Sirhan continues. "And it struck me, then, that there's only one commodity that is going to appreciate in value as time continues: reversibility."

"Reversibility? That doesn't make much sense." Pierre shakes his head. He still feels slightly dizzy from his decanting. He's only been awake an hour or so and is still getting used to the vagaries of a universe that doesn't bend its rules to fit his whim of iron – that, and worrying about Amber, of whom there is no sign in the hall of growing bodies. "Excuse me, please, but do you know where Amber is?"