‘Orders!’ shrieked Sir Thursday. He turned and pointed at Arthur. ‘I am ordering my soldiers to kill all the Piper’s children, starting with this one! Is there no one here who knows their duty?’

‘Nobody move!’ snapped Marshal Dusk, his voice cold and penetrating. ‘That is not a legal order. We are soldiers, not gallows-hands.’

‘You are nothing!’ screamed Sir Thursday. ‘I demote you to nothing. I will carry out my orders myself.’

He twirled, lifted his sword so that it pointed straight at Arthur’s heart, and ran straight at the boy.

Arthur tried to throw himself forward to the ground, but he was held too fast. He could not avoid the thrust.

But the sword did not strike home. Sir Thursday had only taken a single step when the snake wound around the hilt suddenly uncoiled and reared back. It was made entirely of words, and one line that ran down its back suddenly shone silver. The letters grew to the full width of the reptile, spelling out a single phrase: Let the Will be done!

The snake’s fangs gleamed in the silver light, and it struck before Thursday could take another step, its top jaw snapping down on the back of his hand, biting deep. Sir Thursday’s hand jerked, lifting the sword so that the blade whistled well above Arthur’s head, sliced the ear off the Denizen holding him, and then embedded itself in the wooden panelling of the wall.

Arthur heard the Denizen behind him scream and felt him let go. Sir Thursday was trying to rip the snake that was Part Four of the Will from his hand. The Marshals were drawing their swords. Everyone else was huddling back against the walls, some drawing weapons, but most just watching in stunned amazement and fear.

Arthur knew what to do. He spun around, reached up, and, exerting every last ounce of his strength, pulled the sword out of the wood. It clanged onto the ground, because it was too heavy for him to hold up. Arthur knelt beside it and gripped the hilt.

Then he spoke in the clearest voice he could muster.

‘I, Arthur, Anointed Heir to the Kingdom, claim this Key and with it …’ Sir Thursday howled in rage, plucked the snake from his hand, and threw it across the room. Then he snatched a sword from the nerveless hands of a staff major and, still howling like a beast, ran at Arthur.

His path and his swordplay were blocked by the Marshals. It took all three of them to do it, their blades clashing and weaving as they fought to hold off the ravening monster that Sir Thursday had become.

Arthur spoke faster and faster, his gaze on the lightning-fast interplay of swords.

‘With it command of the Glorious Army of the Architect, and mastery of the Great Maze. I claim it by blood and bone and contest. Out of truth, in testament, and against all trouble!’

Something touched his leg and Arthur shrieked, rather spoiling the momentary silence that had fallen as he finished claiming the Key. He looked down and saw the snake spiralling up and around his leg.

The Marshals took advantage of Sir Thursday’s momentary distraction, backing him into a corner, but he was neither disarmed nor defeated. It was all the three Marshals could do to keep him there and protect themselves from his lightning lunges and cuts. He might no longer have the Fourth Key, but he was still extremely dangerous.

‘Point the Key at him and order him to stand to attention,’ hissed the Will. It had coiled most of its body around Arthur’s upper arm and stretched up from there so its diamond-shaped head was unnervingly close to his ear.

‘I don’t want to use the Key,’ whispered Arthur.

‘What!?’ hissed the Will. ‘I know you’re the Rightful Heir! I can tell!’

‘Yes, I am,’ Arthur whispered back. ‘But … look, we’ll talk about it later.’

‘So you have my Key,’ called out Sir Thursday. He lowered his sword, but the Marshals did not press home their attack. ‘However, it takes more than that to command my Army, particularly when the enemy is at the gates. I take it the enemy is still at the gates?’

‘Yes, sir,’ said a colonel uncertainly. ‘But we are confident that when the tiles start to move again, the enemy will lose heart –’ ‘The tiles will not move,’ said Sir Thursday. ‘Due to treachery, I failed. The spike was not destroyed.’

His words were met by gasps, suppressed moans, and even one or two outright cries of despair. Several officers looked away; only a very few looked to Arthur. Their behaviour indicated that the situation was very bad, and now that Arthur thought to listen, he could distantly hear the sound of battle, though there was no cannon fire.

Which was either good or bad, depending on whether it was due to lack of Nothing-powder or because whatever attack was in progress wasn’t that serious.

‘I am Lord Arthur, the Rightful Heir of the Architect,’ Arthur announced. ‘I am assuming command. Marshals Dawn, Noon, and Dusk, I want you to disarm and arrest the Denizen formerly known as Sir Thursday.’

‘I command the Army by order of Lord Sunday, conveyed in writing by Superior Saturday,’ countered Sir Thursday. ‘Perhaps I was hasty in demanding the Piper’s children be executed, but we are at war. Surely you all know that I am the only one who can lead us to victory over the New Nithlings. Arrest this Arthur, and in due course we can look into his claims and hold a proper court of enquiry.’

‘Use the Key!’ hissed the Will.

‘The Will of the Architect has chosen me,’ said Arthur desperately. He raised his arm to show the snake. ‘This is Part Four of Her Will.’

He could feel the mood of the Denizens in the room changing. They would so easily fall back into the familiar pattern of obedience to Sir Thursday.

‘What Will?’ asked Sir Thursday. He took a step forward, and the three Marshals stepped back, their weapons lowered. ‘That is merely a sorcerous snake, a thing of the Upper House. An embellishment to the Key. Colonel Repton, you are close there. Arrest Lieutenant Green, as he actually is. You see that he cannot use the Key, don’t you?’

‘Use the Key!’ hissed the Will again, desperation coming through in its soft serpent voice.

Twenty-six

‘ I AM THE Rightful Heir, you know,’ said Arthur, with weary resignation. He lifted the Fourth Key. It shrank as he raised it, transforming itself from a sword into a slender Marshal’s baton of ivory wreathed in tiny golden laurel leaves. The baton began to glow with a green light reminiscent of the Great Maze’s moon as Arthur held it up. He levelled it directly at Sir Thursday, keeping it in line with the Trustee’s now strangely yellow-tinged eyes.

‘Atten-hut!’

Everyone in the room stood at attention, except for Arthur and Sir Thursday. The Trustee’s eyes grew even more yellow, and a vein stood out and began to throb upon his forehead as he tried to resist the power of the Key. Then, ever so slowly, his boots began to slide across the floor, coming together with a loud click of his heels. His hands went to his sides, and the sword he’d taken angled back to rest on his shoulder.

‘You are stripped of all rank and privileges,’ said Arthur. His voice echoed with power, sounding deeper, stronger, and much scarier than any boy’s should.

Sir Thursday’s epaulettes flew off and his buttons rained upon the floor. His sword snapped into three pieces and the hilt became rusty powder in his hand.

Arthur lowered the Fourth Key.

‘Marshal Dawn, take whoever you need with you and get Sir Thursday locked up somewhere safe. Make sure he can’t escape, but also make sure he is guarded from outsiders too. Somebody is killing all the former Trustees.’

‘Yes, sir!’ snapped Dawn. She took off her belt and used it to bind Sir Thursday’s hands. He did not resist, but he glowered at Arthur, his deep-set eyes staring at the boy with undisguised hatred. Dawn gestured at two colonels to help her, and together they led Sir Thursday from the room.

‘Good riddance,’ said the Will. ‘Now, Lord Arthur, the situation is quite grave. I believe that our first step should be to try Sir Thursday in a properly constituted court so that he can answer for his many crimes –’ ‘Marshal Noon,’ said Arthur, using two fingers to hold the snake’s mouth shut, ‘has anyone tried negotiating with these New Nithlings?’

Marshal Noon looked at the frustrated Will coiled on Arthur’s arm, then back at the boy. ‘No, sir. It has never been possible to negotiate with Nithlings.’

‘My brother is a soldier,’ said Arthur. ‘An officer. He told me once that every army always fights its current war as if it were the previous one, learning no lessons from what is actually happening.’

‘Yes, sir,’ said Noon – but he looked puzzled.

‘What I mean is that we are being attacked not by the old kind of Nithling. These are New Nithlings. Everything is different about them. And they are led by the Piper. At least I guess it’s him. Sir Thursday thought so, and he’d have no reason to lie about that. Which makes me wonder what the Piper and his Nithlings actually want.’

‘To destroy us, sir,’ said Noon.

‘That’s what Nithlings usually want,’ said Arthur wearily. ‘But like I said, everything is different about these New Nithlings. Otherwise we wouldn’t even be in this situation. Which reminds me, what is the situation?’

‘It’s serious,’ Noon reported. ‘We should view the battlefield, but in essence, the New Nithlings around the Citadel continue to be reinforced. There was an assault half an hour ago, which nearly carried the outer southwest bastion. We are low on firewash, have very little Nothing-powder, and the garrison is not up to full strength. The New Nithlings are constantly reinforced, while we are not. We have a force of seventeen thousand, two hundred and eighty-six at last report in the Citadel, and about another sixty-two thousand troops at the White Keep, Fort Transformation, the Cannon Arsenal, and Irontoe Hold. But with the tiles stopped, there is no way we can be reinforced in time by marching, as it is too far. Besides, they will be beset themselves, since there are so many enemy in the Maze. The enemy force against us here numbers at least seventy-five thousand, with tens of thousands more on the march. Without tectonic strategy, we cannot prevent their arrival.’

‘Lord Arthur,’ interrupted the snake, which Arthur had let go. ‘If the Citadel is in danger of falling, then we should leave, being sure to take our prisoner so he may answer to justice –’

‘Shut up!’ ordered Arthur. ‘What is it with you Parts of the Will? You can’t see the forest for the trees. Besides, even if I was going to leave – which I’m not – I’m sure there’s no way out except the Improbable Stair, which I am not going to take, because I do not want to use the Key! Is that clear?’

‘Yes, sir,’ mumbled the snake.

‘That reminds me.’ Arthur fumbled in his pouch and took out the crocodile ring, sliding it on his finger. But he didn’t dare look at it straightaway, and he welcomed an interruption from Marshal Dusk.

‘Pardon me, sir,’ said Dusk. His uniform was a dark grey with black epaulettes and black buttons. Like all Dusks, he had the reserve and inner quiet characteristic of a late evening. ‘There is a way out. An elevator from Sir Thursday’s study goes up to the Middle House and down to the Lower House.’

‘An elevator?’ asked Arthur. ‘Do we have telephone connection with the rest of the House as well?’

‘Yes, sir,’ said Dusk. ‘Do you wish to place a call?’

Arthur tapped the Fourth Key on his thigh, wincing when it actually hurt. The ivory baton was a lot harder than it looked and the gold leaves were pointy.

His mind raced as he tried to work out what to do. Amid the big question of how to defend the Citadel, he had a constant nagging fear for the safety of Suzy and Fred and the other Piper’s children in the raiding party. They’d been frozen or turned into statues or something, which suggested the Piper didn’t want to kill them. He had brought them to the House in the first place, after all. But Arthur couldn’t be sure they’d be all right.

The biggest puzzle was the revelation that the Piper was the leader of the New Nithlings. As far as Arthur could remember, the Piper was one of the three children of the Old One and the Architect, born to a surrogate mortal mother. But he didn’t really know any more than that.

Why would the Piper be leading an army of almost-Denizens against the House? His older brother was Lord Sunday, wasn’t he?

‘Okay,’ he said finally. He paused as everyone in the room looked at him respectfully, anticipation in their faces. ‘How big is Sir Thursday’s elevator? It’s not a stupid little one like at Fort Transformation, is it?’

‘It is of variable dimension, I believe,’ said Dusk. ‘Perhaps the size of this room at its largest extent.’

‘How long would it take to get to and from the Lower House?’ asked Arthur.

‘It depends upon the elevator operators and the local authorities. Minutes, hours, days … I could not say.’

‘Right,’ said Arthur through clenched teeth. ‘I hope it turns out to be only minutes. I want to try to negotiate with the New Nithlings. One other thing my soldier brother once said was that it’s always best to negotiate from a position of strength. So I am going to call on the Lower House, the Far Reaches, and the Border Sea to use that elevator to send through as many Commissionaires, former Overseers, Midnight Visitors, sailors, and so forth as we can round up, with Monday’s, Tuesday’s, and Wednesday’s Dawns, Noons, and Dusks and as much Nothing-powder as we can get together.’

‘Civilians,’ said Noon in a disparaging tone. ‘Though the powder would be useful.’