Arthur’s thoughts submerged into his subconscious as he was hailed by a sentry near the camp.

‘Halt! Who there goes? I mean, who goes there? Recognise me and advance!’

‘Um, I think your name is One-Ear, isn’t it?’ said Arthur. The Denizen was only partially illuminated by the lanterns on Catapillow’s tent, a dozen yards away. ‘It’s Arthur, I’m just coming back from a walk. Doctor Scamandros will be along in a while.’

‘Advance, friend!’ called out One-Ear. He lowered his crossbow and waved Arthur in. As the boy passed, the Denizen muttered, ‘Actually my real name is Gowkin, but One-Ear sounds so much better. I was a Third-Class Box Shifter before the Deluge. Now I’m a forecastle hand —’

‘One-Ear! Watch your front!’

Arthur recognised that shout. Sunscorch came stomping down the beach. Arthur could just make out another sentry behind him, scanning the darkness, his crossbow ready.

‘Aye, aye, sir!’ called One-Ear. ‘Just admitting a friend.’

Sunscorch gave a slight bow as he met Arthur, which the boy returned.

‘The Doc done what’s needful?’ asked Sunscorch.

‘I think so,’ said Arthur. He held up the mirror and shell. ‘He’s given me something I can use to see what’s happened to my friend Leaf. Only I need someone to keep watch while I’m using it. I was hoping you wouldn’t mind . . .’

‘Watch over you? Aye, I can do that. I have to finish going round the sentries first, since we don’t want Feverfew and his lot arriving unannounced.’

‘I thought we left them behind!’ said Arthur as he fell into step with the Second Mate.

‘Maybe, maybe not,’ said Sunscorch. ‘Feverfew’s an uncommon clever sorcerer. Doctor Scamandros would outdo him in book learning, but that pirate must have dozens of filthy tricks the Doc don’t know about. Watch your front!’

The next sentry scrambled to her feet and picked up her crossbow. Sunscorch gave a disgruntled snort and kept on.

‘Doctor Scamandros told me he was a volunteer,’ Arthur said. He needed to know more about Scamandros. ‘What did he mean? Why would he volunteer?’

‘Before the big flood there were only Navigator-Sorcerers on the regular ships,’ explained Sunscorch. ‘So when all the extra ships were being built, they advertised for volunteers with enough sorcerous training to come aboard. Some of the regular sailors were transferred to the new ships too.’

‘Like you,’ guessed Arthur.

‘Yes, sir, like me,’ said Sunscorch heavily. ‘Fourth Mate of the Spiral Waterspout, I was, and you never saw a better ship and a finer crew.’

‘But why would Doctor Scamandros volunteer to be a navigator if he was a top-class sorcerer trained in the Upper House?’

Sunscorch shrugged.

‘He probably lost something. That’s why most folk from other parts of the House come to the Border Sea.’

‘I don’t understand.’

‘Anything that’s ever been lost anywhere turns up in the Border Sea sooner or later,’ said Sunscorch. ‘Finding it again can be more than a mite difficult, though. And it has to be lost by accident — not on purpose, or stolen.’

They were almost down to the sea again. A Denizen stood in the wash, looking out to the water, a crossbow at her side. There were a few very red, very bright stars in one patch of the sky, but it was mostly cloudy, and there was no moon of any kind. Possibly no moon circled this world.

‘Halt!’

‘It’s Sunscorch and the passenger,’ said Sunscorch. ‘All quiet?’

‘Nothing save the waves,’ said the Denizen. Arthur recognised her voice. It was the one with scales all over her face. Lizard.

‘Mind your eye,’ said Sunscorch. ‘If they come, like as not it’ll be straight from the sea.’

‘Aye, aye!’

Sunscorch turned back and started walking up the well-trodden patch of sand between two of the larger piles of boxes.

‘That’s my rounds done. Where do you want to look into that mirror of yours?’

‘Somewhere quiet, with a bit of light,’ said Arthur. He pointed to a patch of sand where there were no resting Denizens, not too far from the lanterns on the tent. ‘Over there would do, I guess.’

Sunscorch followed Arthur over, and stood behind him as Arthur sat down cross-legged on the sand. The boy looked in the shell, holding it up to the light, and shook it a few times to make sure there was nothing inside. Then he gingerly put the shell to his ear, raised the mirror, and tilted it so it caught some of the lantern light.

All Arthur could hear at first was the soft roar of the sea inside the shell, and all he could see in the mirror was his own reflection. He tried thinking about Leaf, but for some reason he couldn’t remember exactly what she looked like. He could remember her voice, though, and he concentrated on that, recalling what she had said when she’d come into his hospital room.

The roar in the shell cut off, to be replaced by the rattle of iron and the creak of wood. The mirror clouded as if Arthur had breathed on it, then cleared to show not his reflection, but another dark scene, lit by a different light.

Arthur stared at the mirror. He could see Leaf, inside a very cramped, dimly lit room.

She was a prisoner.

Twelve

LEAF WAS SITTING slumped in a narrow space, with an inch or so of water around her legs. A heavy chain joined the manacles on her wrists to the manacles on her ankles, then ran to a dark iron ring set into the wooden wall. From the way the water gently sloshed from side to side, she was clearly aboard a ship. The only light came from a swinging, smoke-grimed lantern that hung from a hook in the planked ceiling, barely a foot above Leaf’s head.

Something moved in the darkness in the corner of the vision. Arthur shifted his head to try to see it, but that didn’t work. The mirror was like a TV set or a stage. Anything that happened to either side or behind it was invisible.

The movement came again. Leaf raised her head and looked around. Seeing nothing, her head slumped forward. It looked like she was totally despondent, till Arthur noticed that she was doing something to the manacle on her left ankle. Trying to pick it, he guessed, catching a glimpse of a nail file or something similar.

Arthur was concentrating so hard on what Leaf was doing to the manacle that it took a moment for him to realise he’d seen movement again. This time, the movement ended within the mirror’s frame and Arthur had a clear look at what it was.

A rat. But not just any old rat.

This was a four-foot-tall brown-haired rat that stood upright on its hind legs. It was also wearing clothes. It had on an old but well-kept swallow-tailed coat of dark blue with gold facings over a cream shirt and silver waistcoat, with white breeches that were rolled up to be out of the sloshing water. Its feet were bare and its pink, hairless tail flicked around behind.

The rat lifted its broad-brimmed but low-crowned hat of oiled leather and said in a voice that squeaked when it took in a breath, ‘Excuse me, Miss. Are you by any chance a mortal from Earth?’

Leaf started and scuttled back, her chains rattling.

‘I beg your pardon,’ said the rat. ‘I didn’t mean to startle you. I would not intrude, save that I have a commission regarding a mortal from Earth.’

Leaf shook her head and blinked a few times.

‘Sorry,’ she said. ‘I just kind of . . . wasn’t expecting . . . a . . . a visitor.’

‘Allow me to introduce myself,’ said the rat. ‘I am Commodore Monckton, officer in charge of the Raised Rats of the Border Sea.’

‘Raised Rats?’ asked Leaf weakly. ‘Border Sea?’

Commodore Monckton’s whiskers twitched before he answered.

‘The Raised Rats, young lady, are those rats that formerly served the Piper, and were brought by him to the House. The Border Sea is a demesne of the House, notionally ruled over by Lady Wednesday, self-styled Duchess of the Border Sea and Trustee of the Architect.’

‘Oh, I see,’ said Leaf sarcastically.

‘I beg your pardon?’

Leaf shook her head again. ‘Never mind. Yes, I suppose I am a mortal from Earth. A pretty dumb mortal.’

‘Yet you speak.’

‘I mean dumb like stupid,’ said Leaf. ‘Anyway, what do you want with a mortal from Earth? Can you help me get out of here?’

Monckton took a paper out of his coat pocket and held it out to Leaf. It was Post-it note size when he handed it over, but as Leaf picked it up it grew to full letter size.

The paper showed an engraved portrait of a boy. It was quite a good likeness of Arthur. Underneath it were a few lines of type:

REWARD

Information as to the whereabouts of one

Arthur Penhaligon,

a mortal boy from Earth.

Send particulars by telegram or message to

Monday’s Tierce, Suzy Turquoise Blue

‘Arthur!’ said Leaf. ‘And Suzy was the girl . . . the one with the wings.’

‘Ah,’ said Monckton. ‘You know Arthur? Do you know where he is?’

‘I might,’ said Leaf. Arthur could tell she was thinking from the way her eyes had narrowed a bit. ‘I guess you want the reward?’

‘Naturally,’ said Monckton. ‘Though in this case we have already been paid a small retainer. We are known to be expert searchers and finders.’

‘I’ll tell you what I know if you help me escape,’ said Leaf, holding up her manacled wrists. ‘And help me get in touch with Suzy Blue.’

‘Hmmm,’ mused the Rat. ‘We can’t help you escape, as that would be counter to several agreements we have with various authorities within the House. However, I would be honoured to act as your counsel in the forthcoming court of inquiry into your criminal activities.’

‘Criminal what? What! The only thing I’ve done is let them drag me onto this ship! They took one look at me, asked my name, and then threw me down here in chains!’

‘I believe that you will be charged with being a stowaway,’ said Monckton, adding emphasis with a flick of his tail. ‘The penalty is likely to be one or two hundred lashes, which I suspect you would not survive. Or, to be quite frank, being mortal, you would definitely not survive.’

‘Lashes? You mean like whipping?’

‘Indeed. With the cat-o’-nine-tails. Perhaps you’ve heard of it?’

‘I don’t want to hear about it! Or feel it either! This is crazy. There must be something I can do.’

‘It depends upon the court,’ said Monckton. ‘I suspect there is a logical flaw in the charge, which if correctly argued would result in you being spared punishment.’

‘What is it?’

Monckton inclined his head a little to the side and looked at Leaf with one bright eye.

‘We are mercantile rats, Miss,’ he said. ‘That is to say, you tell me what you know about Arthur, and I shall act as your counsel at the court.’

‘How do I know that you’ll do anything for me once I tell you about Arthur?’ asked Leaf.

‘I give you my word as a Raised Rat and former mortal inhabitant of Earth,’ said Monckton, placing one claw over his neatly waistcoated heart. ‘In the name of the Piper, who brought us here.’

Leaf looked at the Rat carefully. He met her gaze and didn’t blink.

‘Okay,’ said Leaf. ‘I suppose I don’t have much choice. You sound convincing, at least. Better than the guy who sold my dad his last car. I was visiting Arthur in his hospital room, back on our . . . back on Earth. Arthur had an invitation from Lady Wednesday, to have lunch, and he was telling me about the House and everything. Then a giant wave came through the hospital room and swept us out to sea, on Arthur’s bed. We were getting washed up and down these really big waves when a ship with bright green sails picked me up with a rope, but they missed Arthur. I guess he’s still floating on his hospital bed somewhere. If it hasn’t sunk or been picked up by someone else. That good enough for you?’

‘It is an excellent lead, thank you,’ said Monckton. ‘It also explains why the Captain and crew of this vessel have been so tediously closemouthed and have chosen to raft up here at the Triangle. Were it not for some of the regular rats, I would not even have known there was a mortal aboard. I suppose the Mantis was meant to pick up Arthur for Lady Wednesday, and having failed in their mission, Captain Swell is biding his time trying to work out what to do next. Besides get rid of you, the unfortunate evidence of having picked up the wrong mortal.’

‘Raft up? The Triangle? Where are we?’

‘We are aboard the Flying Mantis on the orlop deck,’ said Monckton. ‘A ship of Wednesday’s regular merchant marine. The Mantis is rafted up, which is to say moored to another ship, which is moored to another ship, and so on, all of them ultimately joined to a giant triangular mooring-post that is all that remains above sea level of the old Port Wednesday lighthouse. Hence, the Triangle. Which is, of course, in the Border Sea of the House.’

‘Which is the centre of the universe,’ said Leaf. ‘At least that’s what Arthur said. My parents’d freak if they knew it was like this.’

‘I beg your pardon?’

‘They think there’s some big tree at the centre of the universe, with little branches going off everywhere. And animals living in harmony and being nice to each other and everything.’

‘It sounds rather pleasant,’ said Monckton. ‘If only it were so. Now, I must be getting back to my ship. I shall stop off on the way and inform Captain Swell that I shall be your counsel. I imagine the court will sit anytime within the next few days.’