They lost a little height and the base of the palace brushed across the tops of some particularly tall trees. The dislodged snow plummeted onto the camp followers travelling beneath, adding to their discomfort and vexation. They sent up an anguished roar of protest. The steersman gingerly began to regain altitude.

‘Oh, do get a move on!’ Melyobar grumbled. ‘We’ve no time to waste!’

The startled handler’s concentration was fractured. His hand jerked on the wheel, just enough to move the leviathan a degree off course. He struggled to right it.

Inexorably, the palace slowly glided towards the right-hand cliff wall. There was a series of loud crashes, followed by an intense grinding noise as it scraped along the cliff face. Everyone in the wheelhouse, a score at least of functionaries and guards, had their teeth set on edge. The room shuddered. Glassware and china crashed to the floor.

The Prince seemed supremely unaffected, or curiously unaware of what was happening.

Gradually the palace corrected itself and resumed its stately trajectory, but no more than half a minute of relative calm ensued. A sharp bend in the valley loomed ahead, and in order to negotiate it safely the palace’s speed had to be further reduced. It was a delicate operation. If the speed dropped too low it could cut off the magical supply, and their means of support.

Taking what felt like an age, with Melyobar’s obvious impatience a constant background presence, the steersman took them round the serpentine curve. He was aided by two assistants now, working a bank of levers that operated a complicated system of rudders.

When at last they were back on the straight, to many suppressed sighs of relief, Melyobar again urged more haste. As the valley opened out at that point, the palace could increase its pace.

At the rear, the entourage followed, a line of drones trailing their mammoth queen. They swarmed at the bend in a hovering queue, each slowing as much as they dared to traverse the turn. But one of the last, a multi-turreted affair faced with alabaster, approached a grandiose castle that lay in its path too fast. The speeding structure resorted to braking and swerving at the same time. It clipped the castle, sending it wobbling aside, and careered towards a cliff wall. The speeds involved were relative, so to onlookers it was like watching a clumsy underwater ballet.

The ricocheting palace struck the cliff and literally compressed, a good third of its mass compacting in on itself. Chunks of masonry dislodged and fell. For a drawn out moment the building hung in the air, cerulean lightning playing all over its surface. Then the light went out and its compact with gravity was cancelled.

It plunged like a rock.

That part of the horde unlucky enough to be directly below stood no chance. The palace, disintegrating as it fell, shedding screaming occupants, came down as an avalanche. Its impact was thunderous, and released huge billows of dust that even the heavy snowfall was hard put to dampen.

Melyobar stood to get a better view of the chaos visited on the gorge. ‘I believe that was Count Barazell’s residence,’ he observed, addressing no one in particular. ‘Damned bad luck.’ He sank back into his throne, sighing. ‘Still, should keep Death diverted for a while. Every cloud and all that.’ He waved a languid hand at the crew. ‘Full speed ahead.’

The palace gathered momentum. The end of the valley could be seen, and soon the procession would be in the open snow-covered fields beyond.

Melyobar beckoned an aide. The man was ashen, like everyone else in the room; but they differed from the Prince insofar as his features were permanently wan.

‘As soon as we’re clear,’ he said in an undertone, ‘have search parties sent back.’

The aide stooped. ‘Of course, my lord. I’ll have the rescue teams prepare.’

‘Rescue? Oh. Very well, if they find any surviving aristocrats they can bring them out. But tell them to give corpses priority.’

‘Corpses, Highness?’ The aide’s rigid, tight-lipped response made him look like one himself.

‘Just a selection. I could use a couple of dozen.’

‘Does your Highness require any particular kinds of…cadaver?’

‘I’m not fussy. But come to think of it, bodies of the lower orders serve us best, I think.’

‘Very good, sir. Will that be all, Your Highness?’

‘Yes, yes. Get on with it.’

When the official had gone, Melyobar rose, passed a gamut of bowing flunkies and left the wheelhouse. Outside, he was joined by an escort of his personal guard, four strong, who fell in behind him. He led them to a corridor terminating in an oak door. The sorcerer lounging in a chair beside it leapt up, and in a flurry of obsequiousness opened the door and ushered in the Prince and his guard, then squeezed in after them.

They were in a perfectly square, wood-panelled room not much bigger than a large cupboard. The only things in it were a glamoured lighting orb on the ceiling and a book-sized slab of brown porcelain, etched with runes, set into the wall by the door. At Melyobar’s curt order, the sorcerer laid his palm against it.

The room began to descend. Slow at first, it quickly picked up speed, causing the Prince’s stomach to take a little tickling flip. It was a sensation he quite enjoyed.

His private elevation chamber was essentially a box. It sat inside a shaft that ran from this high point to one of the palace’s lowest, with access to various levels in between. Magically generated pressure, drawing from the same energy propelling the castle, moved the chamber up or down at the direction of its wizard operator. Melyobar prided himself on embracing all the latest conveniences.

The limit of the chamber’s capacity was six people. Consequently they were all crushed together, with Melyobar at the centre of the scrum, allowing his bodyguards a unique opportunity to experience his eccentric attitude to personal hygiene. The descent passed in an awkward silence.

When they finally arrived at their destination, to a chorus of expelled breaths, they tumbled into a subterranean corridor. Leaving the sorcerer behind, the group entered a labyrinth of tunnels which led to a lengthy journey through a series of checkpoints and locked gates. At last they came to a pair of heavily reinforced doors guarded by armed men. Melyobar ordered his escort to wait and went in alone.

He was in a large, windowless room with rough stone walls that made it resemble a cavern, though scores of glamoured globes kept it well lit. Perhaps twenty people were working there, most of them sorcerers.

A wizard greeted him. ‘You’ll require this, Highness,’ he added, offering a bulky white mask identical to the one he and all the others were wearing.

Melyobar needed the sorcerer’s help to position it correctly over his nose and mouth. The mask had been soaked in some kind of sanitising agent, mixed with a mild perfume, which made the Prince cough.

‘How goes the work?’ he asked when he stopped spluttering.

‘Well, sire. Would you care to see?’

‘Why else would I be here?’

The sorcerer guided him to the far end of the room. Four huge metal tanks stood there, each with a glass window. Melyobar went to the nearest and peered in, but all he could see was milky liquid. He was about to complain when a spherical, deathly white object bumped against the glass. The Prince jerked back in shock, emitting a startled squeak.

‘No need for alarm, Highness,’ the sorcerer assured him. ‘Nothing here can harm us providing we’re careful.’

Melyobar stared in morbid fascination at the floating corpse’s head. It looked as though it had been a man, but as putrefaction had set in, it was hard to tell. One eye was missing, the other bulged. The flesh was bloated and turning green.

‘Begging your indulgence, Highness,’ the sorcerer went on, ‘but we really do need some more subjects.’