The Module placed a shaped charge rather larger than any projectile the Devastator had ever fired under the base of the magazine vault, then crawled to one side of the flooded compartment, withdrew all its surface sensors into its armoured carapace and switched its listening devices off entirely.

The detonation shuddered through every single one of the Devastator’s sixty thousand tonnes. It raised eyebrows and clinked ice cubes in glasses on adjoining ships. Two senior technicians in the battleship’s security control room looked slowly at each other and then reached for the Maximum Alert panic button. Every alarm on the ship that hadn’t gone off already proceeded to.

Lebmellin got the call about a third after midnight; he was waiting for it, so sensed his communications aide’s stillness as she listened to something more important than the chatter of world news and jam systems reports which usually spoke to her wired eardrum. She closed one eye, checking her lid-screen.

The Chief Invigilator’s comm man was already talking into a brooch phone.

Lebmellin’s aide tapped his elbow once, and spoke the code he was expecting. “Sir; a Court representative has arrived unexpectedly. He’s aboard the Caltasp Princess.”

“Oh dear,” Lebmellin said. He turned back to the industrialist he’d been talking to, to make his apologies.

“It’s on F deck!” the security chief said, slamming the console and looking round the smoke-misted atmosphere of the control room, where lights flashed from most surfaces and every seat was occupied with people punching buttons, talking quickly into phones and thumbing through manuals. “Oh, sorry, Vice Invigilator,” he said, standing quickly.

Lebmellin left his aides in the corridor and strode into the centre of the room, his gaze sweeping round the boards and walls of flashing lights. “Well now,” he said in his best calm-but-determined voice. “What is going on, eh, chief?”

“Something’s broken into the vault, sir. Straight up and in after a power cut; it’s only two bulkheads-fairly thin bulkheads-away from the central chamber now. The last-ditch stuff ought to activate, but as nothing else has stopped it…” He shrugged. “It’s jammed the vault sir, but it can’t get away; we have two microsubs under the hole and four-soon six-crawler units standing by at the side of the hull, plus the duty submarine on its way to the nearest practicable space with divers ready, and all deck surfaces within two hundred metres under guard. We’ve informed the City Marines and they have aircraft and more men standing by. The Chief Invigilator is-”

“Indisposed, I believe,” Lebmellin said smoothly.

“Yes, sir. Unavailable, sir, so we contacted you.”

“Very good, chief,” Lebmellin said. “Please return to your post.”

The Module broke through into the central vault in a cloud of smoke, its carapace glowing red hot. A machine gun opened up, sprinkling the Module with fire; it lumbered on regardless, dragging a wrecked track behind it. One of its arms had been torn off and its casing had been dented and scarred in various places.

Gas gushed into the circular space, filling it with unseen fumes that would have killed a human in seconds. The machine trundled and squeaked to the centre of the chamber where a titanium sleeve had descended from the ceiling to cover the transparent crystal casing around the Addendum itself.

The Module mortared a shaped-charge fusing pin at the point where the titanium sleeve disappeared into the ceiling, piercing the armour and jamming the sleeve in position. A pulse weapon fired, filling the hazy, gas-choked chamber with sparks but failing to scramble the Module’s photonic circuitry.

The machine extracted what looked like a very thick rug about a metre wide from an armoured compartment under its carapace, wrapped the rug clumsily round the titanium column using its one functioning heavy arm, then sent the light pulse triggering the pre-patterned close-cutter; the charge blasted four microscopically thin crevices through the metal, and a metre of the titanium sleeve fell apart to reveal the undamaged crystal dome within holding the Crownstar Addendum, like a seed cluster within a halved fruit.

The Module loosed its most delicate arm from a slot on its side and reached towards the crystal dome, a hypersonic cutter humming on the end of the spindly arm. It made an incision round the base of the thick crystal dome, lifted it carefully off and placed it to one side, then reached in for the Addendum, lying on a neck-shaped slope of plain black cloth.

The three multi-jointed digits closed in on the necklace, swivelling and adjusting as they neared, as if uncertain how to pick it up.

Then they slowed, and stopped.

The Module made a gasping, grinding noise and seemed to collapse on its tracks. The arm reaching for the Addendum sagged, lopsided, its metal and plastic fingers still a couple of centimetres away from its goal. The fingers trembled, flexed for one last time, then drooped.

Smoke leaked from the carapace of the Module, joining the gas and the fumes and smoke already filling the chamber. A noise like a groan came from the battered machine.

It was quarter of an hour before the emergency motors were able to grind and force the vault round so that its door and the magazine sleeve door were aligned, and before the central chamber was cool and gas-free enough for Lebmellin, the security chief and the other guards to enter.

They wore gas-masks; they stepped in, over pieces of wreckage still glowing, and found the Module where it had stopped, its thin metallic arm stretched out grasping for the Addendum. The guards eyed it warily; their chief looked round the wrecked chamber with a look of disbelieving fury.

Lebmellin stepped gingerly over a lump of sliced titanium, holding his robes up off the debris-scattered deck. “Perhaps we ought to rename the ship the Devastated, eh, chief?” he said, and chuckled behind his mask.

The security chief gave him a bleak smile.

Lebmellin went to the necklace, staring intently at it without touching it.

“Best be careful, sir,” the security chief said, his voice muffled by the mask. “We don’t know that thing’s really dead yet.”

“Hmm,” Lebmellin said. He looked round, then nodded at the security chief, who motioned the guards out of the chamber.

The two men went to a metal fire-hose cabinet on the wan and each inserted a small key into what looked like an ordinary, non-locking handle. The dented mild steel cabinet swung open and Lebmellin reached in under the remains of the ancient canvas hose for a thin package wrapped in clean rags.

Lebmellin peeled back the rags to reveal the real Crownstar Addendum, which of course was far too valuable to leave the vault or ever be left exactly where people thought it was. The two men took magnifiers from their pockets and stared at the necklace. They both sighed at the same time.

“Well, chief,” Lebmellin said. He reached inside his robe with the hand not holding the Addendum and rubbed his chest. “It’s here, but we are going to have to fill out an awful lot of forms, and probably in triplicate.”

At exactly that point, the Module made a noise like a shot, and moved briefly on its tracks before falling silent again. The security chief spun round, eyes wide, a cry starting in his throat. After a moment he turned back. “Probably just cooling,” he said, smiling shamefacedly.

The Vice Invigilator looked unimpressed. “Yes, chief.” He covered the necklace in his hand with the rags and put it back in the fire-hose cupboard; they locked it together.

Lebmellin nodded at the machine. “Have the men force that thing back out the way it came,” he said. “Let the units under the ship take it away; we don’t want it doing anything awkward like self-destructing now, do we?”