Katie wrote "You" on her notepad and put a tick next to the word.

She often did that, let the questions move on and then make notes for a moment which was gone. Putting pencil to paper the instant something of interest arose sent out the wrong signals and that was something Katie tried to avoid.

"Let's try something else," she said. "Something simpler." Folding a piece of paper in two, she dripped red ink into the crease and neatly folded together the two sides, so that the colour oozed between the pages. And then she peeled them apart again.

"What do you see?" said Katie. "You can tell me."

And without a word Prisoner Zero stood up and shuffled to the door, shackles dragging and wires still trailing from his skull, the tiny EEG box scuttling through the dust behind him like some exotic household pet.

A circle may begin at any point. For the 2023 worlds the circle began and ended at Year Zero, in many ways a completely arbitrary choice.

From one and a half million miles away the darkness looked like a slowly turning shoal of shadows with odd and ersatz quasar tendencies. Most astronomers regarded this as a misreading of old data; those who didn't varied in their interpretations as to what the object might be.

One view was that the dark shoal was actually an asteroid belt wrapped stranglehold tight around an unimportant, type II yellow star, one with an energy output of roughly Earth strength.

No one thought the system valuable enough to visit.

Each of the 2023 sections of shell cast a vast area of darkness that swept across the emptiness of space, followed by a narrow fan of sunlight. This was, of course, an entirely humanocentric interpretation of the energy data.

Most of those who later wrote about the arrival of the first Chuang Tzu did so from the comfort of one of the 2023 worlds, and as few ever moved beyond that comfort or felt the need to examine their lives from outside, many now regarded existence beyond the worlds as myth and the arrival of the SZ Loyal Prince as an improving, morally enlightening fairy story.

Had the sun-circling sphere been solid instead of made up of 2023 potentially locking but currently unlocked sections, the area created would have made a single continent over 650 million times the entire area of the Earth. As it was, each of the 2023 sections had nearly three hundred thousand times more living space than the world from which the crew of the SZ Loyal Prince originally came.

Zaq knew all this, of course, because the great, glorious and correct knew what the butterflies knew and the butterflies knew what the Library showed them.

From one side of the unfinished shell to the other was 298.2 million kilometres, which was actually fractional in a galaxy that contained several hundred billion stars and stretched a hundred thousand light-years from rim to rim. All the same, many chose to regard the distance from one side to the other of the 2023 worlds as beyond imagining.

It simplified life.

Once the area around the sun had been occupied by planets. Three, maybe four solid bodies filling what became the emptiness between the 2023 fragments of shell and its star, with another five, mostly gas giants, slung out along the same plane beyond where the shell now hung.

The inner planets would have been iron rich, because this is the nature of inner planets of their age; while the outer planets would have been mainly hydrogen, with helium, water vapour and methane. Now all were gone and only the 2023 worlds remained.

So it was believed by those who held that the sun was natural.

Those who held that the sun was as manufactured as the worlds which surrounded it refused to accept the existence of the missing planets. In answer to the question, "From where did the matter to make the worlds come?" they asked another, "How could the breaking of nine planets possibly produce sufficient matter to create 2023 worlds?"

Such argument came later and had no relevance to the crippled Chinese freighter that limped out of an asteroid storm and settled near the underside of a slab of flat black glass a million kilometres thick. Loyal Prince to the Heavenly Ruler of the Celestial Kingdom of Great Peace was originally a single-engined, ShenZhou-class battle-cruiser, retrofitted as a refugee ship. She'd been drifting for fifteen generations Earth time.

For much of this period SZ Loyal Prince had been broadcasting a distress signal. Throughout the first five hundred years the signal had been in Mandarin, changing to standard English for the century following this. And then, when Colonel Commissar Lan Kuei finally brought herself to accept that her distress call would never be answered, she changed it back to Mandarin.

It was a matter of pride.

Her navigator, Lieutenant Chuang Tzu, was really called something else. He was one of those single sons, the little emperors, spoilt beyond belief but also bowed down under the expectation of his maternal grandparents, who had adopted him after his parents died.

Between the spoiling, the expectation and the impossibility of appreciating one sufficiently or meeting the demands of the other, the boy had fallen into a world of dreams, hence his nickname.

He was also one of the few crew members awake when the Loyal Prince fell into position beneath the edge of a glass slab so enormous that the entire Chinese Republic would have made but a splash on its surface.

"Take us in," the Colonel Commissar ordered.

From far off the line of sunlight between one impossibly vast slab of glass and the next looked knife-blade thin as the SZ Loyal Prince rose steadily towards it. And it was only when her navigator rechecked the distances that Colonel Commissar Lan Kuei realized the gap was actually wider than the distance from her own planet to its moon, easily large enough for an entire fleet of cruisers.

"Steady as she goes..." The Colonel Commissar watched Lieutenant Chuang Tzu smile at her order and pretended not to notice. The boy was useless but very pretty. Besides, being useless was hardly a handicap for the post of yuhangyuan aboard the Loyal Prince.

The ship more or less steered itself.

Once into the gap, the edges of the vast glass slabs seemed claustrophobically close, even though all readings indicated that the nearest was still a hundred thousand kilometres away.

"Shit," said Lieutenant Chuang Tzu.

The Colonel Commissar had to agree.

Besides the Colonel and her navigator there was only one other member of the crew still awake when the SZ Loyal Prince slipped between two worlds and found itself within an almost oppressive shell of matter. This last was Dr. Yuan, who died too soon after this to be properly remembered.

There were, of course, other members of the crew. Although whether they were sleeping or dead was open to interpretation. The Colonel Commissar's view was that they were sleeping. Her navigator, who despite his Chuang Tzu nickname was less of a dreamer than the Colonel Commissar imagined, was of the firm opinion that they were dead. He based this on the fact that some of them had begun to smell.

"Distance?"

"One hundred thousand, Madame."

She'd meant the distance until they reached the upper edge of the vast glass slab, but the Colonel Commissar didn't bother to correct the boy. She was asking questions for the sake of it.

A tall woman with broad shoulders, Colonel Lan Kuei hated her given name, which meant little orchard, and walked with a stoop unless in uniform, when she'd throw out her substantial chest and stride down the half-lit corridors.

She was in command of a dying ship with her effective crew reduced to one. A rip had opened the double hull of the Loyal Prince and their oxygen was leaching away through gates which were designed to be airtight. It was only a matter of time before the atmosphere became too thin to breathe and in deciding to enter the broken puzzle of the sun-circling sphere the Colonel was choosing a place for her ship to die.