She stopped flapping her wings. The sensation of movement remained, and Suzy thought about the situation. Just flapping about aimlessly had produced no results, so she had to do something else.

‘Hey!’ Suzy called out. Her voice sounded very loud in the quiet. ‘Lieutenant Keeper! I’m lost in your stupid Door! Come and help!’

There was no answer. Suzy crossed her legs and took a cheese, mustard, and watercress sandwich out of her hat. Like the hat, the sandwich was rather squashed, but Suzy ate it with gusto. She had rarely had access to any food at all as an Ink Filler. Since becoming Monday’s Tierce and gaining greater access to the larders of the Dayroom, she had rediscovered the enjoyment of food, even though it was not a necessity for life.

‘Miss Turquoise Blue.’

Suzy jumped up and dropped her crust. Whirling around, she saw a tall, extremely handsome Denizen in a high-collared dove-grey morning coat, his black trousers knife-edge-creased above shining top-boots. His top hat was so glossy it reflected the light from Suzy’s wings like a mirror. He held a silver-topped cane in his kid-gloved hand. His wings, furled behind him, were of beaten silver.

‘Who are you?’ asked Suzy suspiciously.

‘That would be asking,’ said the Denizen pleasantly. His tongue, Leaf noted, was an even brighter silver than his wings. ‘I’ll trouble you to hand me our Spirit-eater’s treasure. We can’t have his work interrupted, can we?’

‘Your Spirit-eater?’ Suzy’s eyes flickered from side to side, hoping to see where this Denizen had come from, or some other potential point of escape.

‘Ours,’ said the Denizen. His voice was extremely musical and pleasant to listen to. ‘Come now. Give me the pocket, and I shall show you a point of egress from the Door.’

Suzy blinked and found her hand reaching under her waistcoats.

‘I’m not giving it over to you!’ she said through gritted teeth.

‘Yes, you are,’ instructed the Denizen. He yawned and patted his mouth with his left glove. ‘Hurry up.’

‘I’m not!’ insisted Suzy, but to her horror, she found that she was taking out the container with its scrap of precious material.

‘Very good,’ said the Denizen approvingly. He reached out his hand to take the box as Suzy stared at it and tried to will herself to move away, to withdraw her hand.

Just as his fingers were about to close on the box, the Denizen’s wings suddenly exploded out behind him and he twisted up and away, snarling in rage. Suzy fell back and somersaulted over twice before her own wings spread out and steadied her.

High above her, the silver-winged Denizen was in a furious duel with an electric-blue-winged Denizen that Suzy did not at first recognise as the Lieutenant Keeper of the Front Door. His blue-fire sword was met by the silver flash of the other Denizen’s sword-cane, the two of them swooping, turning, and diving as they exchanged lunges and blows and blurringly-fast parries and dodges.

Suzy watched openmouthed as the two combatants fought. They used their wings as weapons as much as a means of movement, blocking swords, slicing with the tips, and delivering buffets which if they hit, sent the targeted Denizen somersaulting through space. Sometimes the two were upside down relative to Suzy, or perpendicular, and she got quite dizzy trying to reorient herself before she gave up and just watched.

The swordplay was very fast and very dangerous. Many times one or the other only just managed to parry or weave aside or leap backwards as a thrust went home. Steel clashed on steel so quickly it sounded like a constant jangle of fallen coins. Suzy, who was being taught to fence by Monday’s Noon, felt her eyebrows going up and down in constant surprise as she saw wing-assisted feats of sword-fighting that were in none of the manuals Noon had lent her.

Apart from watching, all Suzy could do was stuff the container with the pocket back into her waistcoat and stay out of the way. She contemplated trying to intervene, but the two combatants moved too quickly and were so focused on the fight that she concluded any move on her part would only put the Lieutenant Keeper off.

Then, as the Lieutenant Keeper went on the defensive, continually retreating upward, Suzy wondered whether she should try to get away. But she still couldn’t see anywhere to retreat to. Instead, she followed the combat, her wings straining to keep up.

Suddenly the Lieutenant Keeper stopped retreating and flung himself forward. The other Denizen tried for a stop-thrust but missed, and the two closed, blades locking. The Lieutenant Keeper was the slighter and shorter of the two, but his wings must have been stronger, for he pushed his opponent back at least twenty feet. At the same time he shouted something, a word that Suzy couldn’t understand but still felt through every bone in her body, like a ripple of ague.

With that word, a circle of white light appeared directly behind the silver-winged Denizen. He must have sensed it, for his wings thrashed even harder to keep his place – but the Lieutenant Keeper was too strong for him.

‘This does not end –’ shouted the Denizen as he fell back into the circle of light. It was a doorway out, Suzy saw, with a gold-panelled room on the other side and an elephant’s-foot umbrella stand. Once the Denizen was through, the circle closed like a bursting soap bubble. Again there was nothing but featureless space all around.

‘Cripes,’ said Suzy. ‘Who was that?’

‘Superior Saturday’s Dusk,’ said the Lieutenant Keeper. ‘We are old adversaries, he and I. Not all the Days or their servants follow the compact of the Door to the letter, and Saturday’s minions are the slipperiest of all.’

The Lieutenant Keeper brushed back his long white hair with his fingers and wiped his face with the sleeve of his blue coat. He still looked harried; his waders were dripping with water and there were more dried blue bloodstains on his right sleeve. ‘Doubtless he will return soon, possibly with others. I have closed many of the doors in the House, but this is of little avail when Saturday orders them open again and Sunday does not say yea or nay. Where do you wish to go, Suzy?’

‘The Lower Hou –’ Suzy started to say. Then she stopped.

‘Can I go anywhere within the House?’ she asked.

‘The Front Door opens in all parts of the House, in various guises,’ the Lieutenant Keeper informed her. ‘Not all those doors are safe. Some are stuck, and some are locked, and some are lost, even from me. But I can show you a door to any of the demesnes, within certain bounds.’

‘Do you know where Arthur is now?’ asked Suzy. She’d planned to take the pocket back to Monday’s Dayroom, but it would be better to get it straight to Arthur so he could destroy it without delay.

‘I do not,’ said the Lieutenant Keeper. ‘Come, decide where you would go. My work is never done, and I cannot tarry.’

‘The Great Maze,’ said Suzy. ‘I want to go to the Great Maze.’

‘The only door I might open there is in the Citadel. That is where Sir Thursday resides. Are you sure that is where you want to go?’

‘Sure,’ said Suzy.

‘There is great trouble in the Maze,’ warned the Lieutenant Keeper. He looked directly at Suzy, his pale ice-blue eyes meeting hers. ‘It is possible that soon all doors to and from the Maze will be closed. Elevators too.’

‘Why?’

‘Because a Nithling Army stands on the brink of conquest there. If they defeat Sir Thursday’s forces, then the Great Maze will be cut off in order to save the rest of the House. So I ask again: are you sure you want to go there?’

‘I got to get this to Arthur,’ Suzy answered, patting the container under her waistcoats. ‘So I reckon I do have to go there. Besides, it can’t be as bad as all that. I mean, Nithlings never get on with one another, do they?’

‘These ones do,’ said the Lieutenant Keeper. ‘Here, as you insist, is the door to the Great Maze and Sir Thursday’s Citadel.’

He gestured with his sword, and once again spoke a word that made Suzy’s stomach flip over and her ears ring. A circle of light formed, and through it she could see a wooden walkway along a stone wall. A Denizen in scarlet uniform was marching along the walkway with his back to her, a musket on his shoulder.

‘Thanks!’ said Suzy. She flapped her wings and was about to dive headfirst into the hole when she felt herself held back by her tip feathers.

‘No wings in the Great Maze,’ said the Lieutenant Keeper. The wings detached themselves from Suzy, dropping into his hands. ‘They attract too much lightning. Something to do with the tile changes.’

‘But I have to give them baaa –’

Before Suzy could finish talking, the doorway moved toward her and she fell through, emerging into late-afternoon sunlight and a cool wind, high on the battlements of one of the bastions of the Star Fort, an inner defence of Sir Thursday’s Citadel.

As Suzy clattered onto the walkway, the sentry suddenly stopped, stamped his feet, and did an about-turn. He took another two or three paces, staring right at Suzy, before the sight of her percolated into his brain. He stopped and fumbled with his musket, eventually bringing it to bear as he stuttered out, ‘Halt! Who goes there! Call the guard! Alarm! Guard! Corporal!’

Twenty

THE NEW NITHLING patrol was easily evaded, the Not-Horses stretching their legs to gallop without the burden of the double-ride sack. Arthur, experiencing this for the first time, was at first terrified and then, after it became clear he wouldn’t just fall off, exhilarated.

The Not-Horses had much greater stamina than earthly horses, but even they could not sustain a gallop for long. After the Nithling force was nothing but a distant speck on the horizon, beyond the low hills of the current tile, Troop Lieutenant Jarrow raised his hand. His Not-Horse slowed down to a canter, then to a brief trot, and finally a walk, with Arthur’s and Fred’s mounts following their leader.

They continued at a walk for the rest of the day, with half an hour’s rest at noon, amid the ruined city of the last tile they needed to cross. It wasn’t much of a ruined city. There were only outlines of old buildings, one or two bricks high, and grassy barrows that might or might not contain interesting remnants. Troop Lieutenant Jarrow explained that there had never actually been a city there. It was built as a ruin, when the Architect had made the Great Maze to be a training ground for the Army.

The officer also showed them how to recognise a tile border – an important thing to know, because anyone within a few yards of a border at sundown ran the risk of having different portions of their body simultaneously transported to different places.

Not all tile borders were marked in the same way, Jarrow explained, but most borders were obvious from a change in the colour of the vegetation or the soil, showing up as a continuous line. The border from the jungle to the ruined city, for example, was very clear, as every vine-hugged tree on the southern edge was almost yellow instead of a healthy green.

The border from the ruined city tile to the marsh was not as evident, since there was no clear line of colour change or difference in vegetation. But Jarrow pointed to a low cairn of white stones in the middle of an area where the ground slowly changed from a short green grass to low shrubs that were almost blue. Significantly, the cairn was a semicircle, round on the northern side and sheer on the south. It had been built to show the southern border of that tile.

The marsh proper began soon after. Jarrow let the reins slack, and his Not-Horse picked a way through the spongy sedge and the tea-coloured pools of water, the others following in single file.

In the middle of the tile, or near enough by Jarrow’s estimation, they found an island of slightly drier, somewhat higher ground, and here they set up camp. Jarrow again kept watch as Arthur and Fred removed the Not-Horses’ harnesses, wire-brushed and oiled them, and polished their ruby eyes. Then they rubbed down their lightning-charged tulwars, sharpened them, and rubbed grease on their boots and their mail hauberks. All in all, this took till dusk.

Deep in the marsh, with the sun dipped below the horizon, they could only see one of the changed tiles around them. Looking to the east, where there had been nothing to see, there was now an imposing mountain, a dark silhouette against the starry sky.

‘We ride to the Citadel in the morning,’ said Jarrow. He’d used the last of the sun to consult his almanac, choosing not to show a light after dark. ‘I’d like to ride now, and if we had different tiles we might have done it. But there’s a mountain pass to go through now, and a forest, and the Eastern Water Defence.’

‘The what water defence?’ asked Arthur.

‘It’s part of the Citadel and doesn’t move. A dry lake that can be flooded by opening sluice gates from the subterranean springs below the Citadel hill. It should still be dry, but …’ Jarrow’s voice trailed off. The three of them sat in the starlit darkness, listening to the sounds of the swamp. Their Not-Horses stood quietly nearby, also occasionally talking to one another in their soft, dry language that perhaps only the oldest of Troop Sergeants might understand.

‘Should be dry, sir, but perhaps won’t be?’ asked Fred after a while, greatly daring.

‘Yes, it may have been filled,’ said Jarrow. ‘While tectonic strategy has proved masterful as always, there are so many New Nithlings around that some were bound to end up near the Citadel, and the different groups have been joining up on the plain below the hill … a nuisance really. Not a siege, not by any means.’

‘What exactly is the Citadel, sir?’ asked Arthur.

‘It’s a mighty fortress, Green. Four concentric rings of bastions, ravelins, and demi-lunes, all sited to support one another with cannon and musket, and the approach ramps covered by firewash projectors. Then, within the third ring, there is the Inner Citadel, a Star Fort built upon a hill of hard stone. The Inner Citadel has earthen ramparts seventy feet thick abutting walls forty feet high, and it is armed with sixteen royal cannon, thirty-two demi-cannon, and seventy-two small cannons the Artillerists call sakers. Though there has been a terrible shortage of powder for them, ever since Grim Tuesday was deposed by this new Lord Arthur –’