Thrial was a ring of pure white gold inset with veins of platinum; it opened on a concealed hinge made from what appeared to be extruded diamond 13. The planets hung on loops of equally unlikely allotropic mercury and were each represented by a flawless example of the relevant birthstone according to the Piphramic Astrology, precisely graded to indicate planetary size on a logarithmic scale. Moons were red diamond, the asteroids emerald dust and the comets a tinily beaded fringe of dark carbon fibres, each tipped with a microscopic sphere of white gold. Distance from Thrial was represented by molecule-wide fines somehow etched into the ambivalent loops of mercury.

The Crownstar Addendum, as the necklace had been called for four or five thousand years, was beyond argument the single most precious piece of jewellery in the system, either extant or missing. All by itself, in its sheer pricelessness, the Crownstar Addendum provided the theoretical security for the Log-Jam’s currency, commercial guarantees and insurance bonds. Its melted-down and split-up value alone would have kept an averagely extravagant noble family comfortably off for a century or so, or even bought a minor house name, but that element of its value was insignificant compared to its intrinsic worth as something precious and mysterious that had somehow survived-and, to the extent that it could, had often been part of-Golter’s frenetically embroiled and feverish history.

Exactly who or what had made it, for whom, and when, and how, nobody knew.

No more did they know what the Crownstar itself was, if there had ever been such a thing. On Golter, the chances were about equal that if the Crownstar had existed it had been hidden, broken up, or just lost.

Whatever the Crownstar had been, and wherever it had ended up, there was no doubt concerning the location of its Addendum; it was kept deep in a special vault located inside a battleship near the centre of the Log-Jam. It was taken out-under intense security-only for very rare and special occasions; it was never, ever worn, and the impregnability of its vault-effectively a gigantic revolving safe made from three thousand tonnes of armour plate-had in recent years become almost as legendary as the fabled necklace itself.

Ethce Lebmellin watched from his plushly decorated seat in the reviewing stand as the two winning yachtsmen acknowledged the cheers of the crowd and started to ascend the steps towards him. The first prize was an ornate and ancient silver cup; it sat in front of him, gleaming in the reflected light striking off the waves. The gaily striped awning above flapped and snapped in the breeze.

Lebmellin looked at the prize cup, studying his reflection on its curved, polished surface. A rather silly prize for a rather silly pastime, he thought. The sort of thing the middle orders tended to waste their lives over, imagining they had accomplished something.

A familiar feeling of self-disgust and bitterness welled up inside him. He felt used and reviled. He was like this cup; this decorative, over-decorated trinket. Like it, he was dragged out for certain ceremonial duties, briefly admired, made use of, then packed away again without as much as a second thought. They were both fussily ornamented, had little apparent practical use and they were both hollow. Was this what he had worked for?

He had spent years in the diplomatic colleges of Yadayeypon, studying hard while the smart-ass lower-order kids made fun of his plodding progress, and the smoothly urbane scions of major houses-and minor houses better off than his own-sneered at his unfashionable clothes.

And what had he received, for all those late nights, all those given-up holidays, all those taunts and sly looks? An undistinguished qualification, while others had drunk and snorted and fornicated their way to outstanding success, and others had simply not cared, their positions in some family concern or Corp guaranteed just by their name.

He doubted any of them even remembered him.

A sinecure; a post of utmost vapidity for a small, parochially eccentric city-state. It was probably no more than his brilliant contemporaries had expected of him.

He rose to present the cup to the two fresh, sweating faces. He let them touch his gloves and kiss his ceremonial rings, wanting to draw his hand away and wipe it, feeling that everybody was watching him and thinking what a fool he looked. He spoke a few predictable, meaningless words to them, then handed the two men their empty prize. They held it aloft, to more cheers. He looked around the crowds, despising them.

You’ll applaud me one day, he thought.

He realised he was smiling, but decided it was only fitting, given the general rejoicing.

He thought of that upstart barrow-thief Miz Gattse Kuma and that snotty aristocrat with her laughing, dismissive eyes. Want to use me to get our treasure? he thought, still smiling, his heart beating faster. Think you can buy just my robe and my cooperation without buying the man inside, with his own desires and ambitions and plans? Well, he thought. I have a little surprise for you, my friends!

The Abyssal Plain Nodule Processing Plant Mobile Repair Module woke up at one second before midnight, its circuits and sensors quickly establishing its location, internal state and external circumstances, as well as its programmed instructions.

It was on Golter, in a shallow lagoon off the coast of Piphram, under the floating city called the Log-Jam; it was fully functional and recently overhauled, with all reservoirs, tanks, magazines and batteries registering 99 per cent capacity or above; a subset of instructions refamiliarised it with the extra equipment and weaponry it had been fitted with, finding those fully ready too.

Its cupola sensor was at a true depth of 27.1 metres; its tracks, two metres lower, were sunk into soft mud to a depth of forty centimetres. Assuming its chronometer to be correct, the tide should be half-ebbed. The keel of a large stationary vessel lay eight metres above it. Light was scarce, seeping in from the occasional gap in between distant ships in shafts that barely illuminated the surrounding mud; the light signature indicated it was artificial. There was a faint current, only a few millimetres per second. The seabed was quiet; the water itself was filled with a distant, inchoate rumble of sound, an amalgam of noises coming from the ships that stretched for kilometres in all compass directions.

Water quality was brackish, oxygen-poor and moderately polluted with a broad spectrum of contaminants, though it was comparatively transparent. There was a confusing jumble of mostly metallic junk and wreckage lying under the surface of the mud at levels from nine metres down to barely submerged. Magnetic fields lay in static patterns all around; distant fluctuations were motors. Electrical activity was dispersed and ubiquitous in the ships above it.

Radiation was normal, for Golter.

Its instructions were clear. It readied itself, then adjusted its buoyancy by dropping two large weights from its flanks; they fell a few centimetres and embedded themselves in the mud, barely disturbing the surface. The mud still held it, but its motors would break that grip. It carried out the quietest possible start, flutter-feeding its motors so that it moved away at first much slower than the current, coming up and out of the mud as its buoyancy brought its tracks to the seabed’s surface.

Using its tracks and impellers, it accelerated smoothly and almost silently up to a slow crawl, and began a wide turn that would take it towards the destination it could already sense; the keel of a long vessel whose girth, allied with the angle of taper from beam to stem and stem, as well as the depth of water the craft was drawing, indicated that it was, or had been, a large capital ship; probably a battleship.