‘Hold on, then,’ said Arthur. ‘We’ll give it a try.’

He looked into the mirror and tried to remember what his quarters in Thursday’s Citadel had looked like. He remembered the big four-poster bed with the carved battle scenes on the posts, and then there was the wardrobe, the chair he’d been shaved in, and, yes, there was a tall, bronze-framed mirror in the corner. If he thought of that mirror like a window, then looking through it he would be able to see the bed, and the door, and the painting on the wall . . .

Slowly, he began to see the room, though much of it was clouded and fuzzy. It took him a few seconds to work out that the bronze mirror was partially covered with a cloth. But he could see enough of the chamber, he was sure, for the Key to open a door there.

‘Fifth Key, take me . . . us . . . to my room in the Citadel of the Great Maze!’

It was not so easy to go through the door of white light this time, nor was the transfer so immediate. Arthur felt himself held back not just by his coattails but by a force that pushed against his entire body and tried to throw him back. He struggled against it, with mind and body, but it was like walking against a very powerful wind. Then all of a sudden it was gone. He fell into his room in the Citadel, and Dr Scamandros fell over his legs. Both of them tumbled across the floor, and Arthur hit his head against the carved battle scenes on the left-hand post of the huge bed.

‘Ow!’ he exclaimed. He felt his head, but there was no blood, and after a moment the sharp pain reduced to a dull ache.

‘I do beg your pardon, Lord Arthur,’ said Dr Scamandros as he got to his feet. ‘Most clumsy of me. That was fascinating – quite a different experience than a transfer plate. I am enormously grateful to you for saving me from the Deep Coal Cellar.’

Arthur stood, using the bedpost to haul himself upright. As he did so, the sleeves of his paper coat rode up. He slid them back down, and for the first time noticed that they finished well short of his wrists. His trousers were also now ridiculously short, real ankle-freezers.

‘I’d better get changed,’ Arthur said. He started toward the walk-in wardrobe, hesitated, and went back to the door, throwing it open to shout, ‘Sentry!’

A startled Denizen in the uniform of a Horde Troop Sergeant hurtled into the room and stood quivering at attention, his lightning tulwar crackling as he saluted with it. Arthur heard the crash of at least a dozen boots out of sight down the corridor, evidence of more troopers suddenly coming from rest to parade-ground attention.

‘Lord Arthur! Guard present, sir!’

Arthur was already in the wardrobe, taking off his paper clothes and quickly putting on the plainest uniform he could find, which happened to be the sand-coloured tunic and matching pale yellow leather breeches of a Borderer on desert duty, though this particular tunic had gold braid stitched across the shoulders and the leather breeches had gold stripes down each leg. Both tunic and breeches were much softer and more comfortable than anything a regular Borderer would ever be lucky enough to wear. They fit perfectly after a moment, shifting and altering themselves from Sir Thursday’s size to Arthur’s new height and musculature.

‘Thank you!’ Arthur called out to the sergeant. ‘We’ll go down to the operations room in a minute. Is Dame Primus here? And Suzy Turquoise Blue?

‘Dame Primus is in the operations room, sir!’ boomed the Troop Sergeant. He appeared to be under the impression that Arthur was either deaf or much further away than he actually was. ‘General Turquoise Blue is somewhere in the Citadel.’

‘General Turquoise Blue?’ asked Arthur. ‘I didn’t make Suzy a general, did I? I remember her talking about it, but I don’t remember actually . . .’

‘She probably just put on the uniform,’ said Dr Scamandros. ‘No one would question her.’

Arthur frowned, but the frown quickly gave way to laughter.

‘That sounds like Suzy,’ he said. ‘I bet she did it to get a better grade of tea or something. Or to annoy Dame Primus.’

He picked up a pair of armoured sandals, looked at them for a moment, then dropped them back on the shelf and chose a pair of plain, but glossy, black boots instead.

‘It’s good to have you back, sir,’ said the Troop Sergeant as Arthur strode out of the wardrobe.

‘Thank you again, Sergeant,’ said Arthur. ‘Let’s get to the operations room. I need to find out exactly what’s going on.’

There were at least twenty guards in the corridor, who formed up around Arthur as soon as he appeared. As they all marched together to the operations room, Arthur asked the guard commander to also send a messenger to find Suzy.

The operations room had grown larger in the few days of House time that had passed since Arthur had been there last. It was still a large domed chamber, but the walls had been pushed back to make it twice the size it had been before. It was now as big as his school’s gymnasium, and in addition to all the soldiers in the various uniforms of the Regiment, the Horde, the Legion, the Moderately Honourable Artillery Company and the Borderers, there were also numerous Denizens in civilian attire, many of them with their coats off and the sleeves of their white shirts covered with green ink-protectors up to the elbow.

Besides the central map table, which was also much longer and broader than it had been, there were now rows and rows of narrow, student-style desks for the civilians, who were all busy talking on old-fashioned phones or scribbling down messages. Every few seconds one would push his or her chair back and race across the room with a message slip, going either to Marshals Dawn, Noon or Dusk, or to Dame Primus, who loomed over the map table, looking intently at various details while many Denizens babbled out messages around her, often at the same time.

Dame Primus was even taller than ever, perhaps eight and a half feet from toe to crown. She was wearing an armoured hauberk of golden scales that clattered as she moved. The whole outfit looked decidedly uncomfortable, and dangerous for others, as it was ornamented with spiked pauldrons made to look like gripping claws. Even though the points of the claws gripped her shoulders, they also had spurs and flanges poking out in all directions.

The gauntlets that comprised the Second Key were folded through Dame Primus’s broad leather belt, next to the buckle. The clock-hand sword of the First Key hung scabbarded at her left hip. The small trident that was the Third Key sat in its holster on her right hip, and she held the marshal’s baton that was the Fourth Key, occasionally gesturing with it.

The cacophony of shouted messages, ringing telephones, scraping chairs and clattering, hobnailed or leather-soled Denizens suddenly ceased as Arthur’s presence was announced. Then the noise redoubled as everyone in the room leaped from their chairs or pushed themselves off a wall, turned to the door, and came to attention.

‘Carry on!’ called Arthur immediately. There was just a moment’s more silence, and then the room erupted into motion once more. The telephone earpieces rattled on their candlestick bodies as the old bells inside clattered more than rang, the messengers ran across the room, and the officers resumed talking all at once.

But the messengers did not get to deliver their hastily scrawled message forms to Dame Primus. She held up one hand and waved them back, striding across the room to greet Arthur with Marshals Dawn, Noon and Dusk close behind her.

‘Lord Arthur, a most timely arrival. I trust you have learnt not to accept gifts from strange visitors?’

It took Arthur a moment to work out that Dame Primus was referring to the package he’d taken from Friday’s servant Emelena, which had contained a Transfer Plate that had immediately activated, taking him to the Middle House. He had forgotten that he hadn’t seen Dame Primus since then, or not all of her, at least. He’d found Part Five, who he quite liked and had hoped would round out the character of the Will, adding some much-needed common sense. Part Five had been assimilated, judging by what he had first assumed was a half-cloak on the back of Dame Primus but now saw were in fact delicate semitransparent grey wings that were very similar to those that had been on the bat-beast that had lurked in the Inner Darkness of the Middle House.

‘I’ll know better next time,’ he said. ‘What I need to know now is what’s happening. Is the Lower House really destroyed?’

‘Apart from the Deep Coal Cellar, the Lower House is entirely lost,’ Dame Primus confirmed. ‘As are the Far Reaches, and Nothing continues to surge against our defences. Only the Keys can strengthen the fabric of the House, and we are threatened on too many fronts for me to deal with everything by myself. If you take the Fifth Key to the Middle House and reinforce the bulwark there, I will go to the Border Mountains here and build them up—’

‘Hold on,’ interrupted Arthur. ‘How did this happen in the first place? And where is the Piper’s Army? Are we still fighting Newniths here?’

‘Really, Lord Arthur, there is no time to waste,’ said Dame Primus. ‘The Piper’s Army has withdrawn and is no longer of immediate importance. Shoring up the foundations of the House is, and only you and I can do anything about that—’

‘What about Superior Saturday?’ asked Arthur. ‘What is she up to? Why does she want the House to fall, and what are we going to do about her? I’m not going anywhere until you, or someone, tells me everything I want to know!’

Dame Primus loomed over him. Though he had grown taller, she was far taller still, and her eyes were narrowed and her mouth was tight with displeasure. Arthur felt a strong urge to step back, even to kneel in awe of her terrible beauty and power. Instead he forced himself to take a step forward and look at her straight in her strange eyes, their pink irises surrounding pupils of intense darkness. She was every inch the embodiment of the Architect’s Will, and Arthur knew that if he gave in to her now, he would never have the chance to make his own decisions ever again.

‘I am the Rightful Heir, aren’t I?’ he said. ‘I want to know exactly what the situation is. Then I will decide what we are going to do.’

Dame Primus met his gaze for a full second, then slowly inclined her head.

‘Very well, Lord Arthur,’ she said. ‘As you command, so it shall be.’

‘Right, then,’ said Arthur. ‘First things first. What actually happened to the Lower House? Did Nothing break through in the Far Reaches?’

‘I will show you, through the eyes of someone who was there.’ Dame Primus gestured with the baton, and all the lamps in the room suddenly dimmed. ‘Mister Skerrikim, I trust you still have the survivor?’

A Denizen in a dark frockcoat, black cravat, and embroidered silver skullcap answered in the affirmative from the back of the room and made his way over to Dame Primus, lugging a large and rather battered leather suitcase fastened with three straps.

‘An elevator operator was just closing his doors when it happened,’ said Dame Primus to Arthur. ‘He managed to get most of the way out of the Far Reaches before the Nothing caught him. By holding on to the ceiling light of the elevator with his teeth, his head and a small remnant of the elevator actually arrived here. Fortunately Mister Skerrikim was just in time to prevent his total dissolution.’

Mr Skerrikim, who Arthur had never seen before, laid the suitcase down on the floor, undid the straps, and opened it up. The case was full of rose petals, and in the middle of the petals lay a disembodied head swathed from temple to chin in clean white bandages, like an old-fashioned treatment for a toothache. The head had its eyes shut.

Mr Skerrikim picked up the head by the ears and propped it against the open lid so it faced Arthur and Dame Primus. Then he took a small bottle of activated ink out of his pocket, dipped a quill pen into it, and wrote something in extraordinarily tiny letters on the forehead of the survivor.

‘Wake up, Marson!’ instructed Mr Skerrikim cheerfully.

Arthur started as the head’s eyes flicked open. Dr Scamandros, who was a step or two behind the boy, muttered something that did not sound very friendly.

‘What is it?’ Marson’s head asked grumpily. ‘It’s hard work growing a new body. Not to mention painful! I need all my rest.’

‘You shall have plenty of rest!’ declared Mr Skerrikim. ‘We’re just going to have another look at what happened down that pit, near the dam wall.’

‘Must you?’ asked Marson. The head’s mouth quivered and tears formed in the corners of his eyes. ‘I just can’t relive it again – the pain of the Nothing as it ate away my limbs—’

‘This is entirely unnecessary!’ protested Dr Scamandros as he pushed past several interested officers to stand next to Arthur. The tattoos on his face were of painted savages dancing around a bonfire, under the direction of a witchdoctor in a ludicrous feathered headdress. ‘This poor chap need not feel his immediate past merely for us to see it! I see also that you, sir, have used a quite discredited spell for the preservation of a head, and I must ask you to relinquish care of this individual to someone who knows what they are doing!’

‘Mister Skerrikim is quite adequately trained,’ said Dame Primus smoothly. She did not look at Dr Scamandros, but spoke to Arthur. ‘As Sir Thursday’s Chief Questioner, Skerrikim has conducted many showings from Denizens’ minds, and as you know, Arthur, Denizens do not really feel much pain. Marson will be well rewarded when his new body grows.’

‘I thought Doctor Scamandros was the only sorcerer not in Saturday’s service,’ said Arthur.

‘Mister Skerrikim is not exactly a sorcerer,’ Dame Primus clarified. ‘It is true he is a practitioner of House sorcery, but his field of specialisation is quite narrow.’