The black bird Gravious flew slowly across the re-creation of the great sea battle of Octovelein, its shadow falling over the wreckage-dotted water, the sails and decks of the long wooden ships, the soldiers who stood massed on the decks of the larger vessels, the sailors who hauled at ropes and sheets, the rocketeers who struggled to rig and fire their charges, and the bodies floating in the water.

A brilliant, blue-white sun glared from a violet sky. The air was crisscrossed by the smoky trails of the primitive rockets and the sky seemed supported by the great columns of smoke rising from stricken warships and transports. The water was dark blue, ruffled with waves, spattered with the tall feathery plumes of crashing rockets, creased white at the stem of each ship, and covered in flames where oils had been poured between ships in desperate attempts to prevent boarding.

The bird flew over the edge of the sea scene, where the water ended like a still, liquid cliff and the unadorned floor of the general bay resumed, just five metres below, its surface also covered with what looked like wreckage - as though the tide had somehow gone out in this part of the bay but not the other - but which on closer inspection proved to be objects - parts of ships, parts of people - which had been in the process of construction. The incomplete sea battle filled less than half of the bay’s sixteen square kilometres. This would have been the Sleeper Service’s master-work, its definitive statement. Now it might never be finished.

The black bird flew on, passing a few of the ship’s drones on the surface of the bay, gathering the construction debris and loading it onto an insubstantial conveyor belt which appeared to consist of a thin line of shady air. It kept beating. Its goal lay on the far end of the doubled general bay, between this internal section and the bay that opened to the rear of the ship. Damn the woman for choosing to stay at the bows, nearest to where the tower had been. Bad luck the place it had to be was so close to the stern.

It had already flown through twenty-five kilometres of interior space, down the gigantic, dark internal corridor in the centre of the ship, between closed bay doors where a few dim lights glowed and utter silence reigned, a kilometre of air below its gently flapping wings, another above and one to each side.