'You must understand that not even Gideon knows the details of our mission,' Denton said. 'We are working in secret for Lady Amilee alone. It is vital that you never tell anyone about where we have been and what we have done. And that includes Van Bam, Marney ... Marney? Are you listening to me?'

Marney supposed she was, in a vague sort of way, but Denton's words could not cut through the awe she was feeling for her surroundings.

She had read about forests; she had heard the other agents talk about them, and had seen artistic representations. But no book, no words, no painting could ever do justice to the world that now filled her sight.

The Trees of the Many Queen, this House was called. Marney and Denton stood side-by-side with their backs to the portal – a wooden doorway framed by two trees – that had delivered them there from the Great Labyrinth. She stared down a bare dirt road that cut through the forest. The air was humid, and the breeze that sighed and whispered through the dense and verdant leaves was damp against Marney's face. The earthy scents that filled her nostrils were somehow clean and wholesome. The buzzing of insects and the occasional flapping of wings were the sounds of freedom.

Marney's breath caught as a distant tapping echoed through the forest, a fast knocking on wood, almost like drilling. It stopped and then started again, repeating several times before the echoes faded away.

'What was that?' she asked in wonder.

A bird called a woodpecker, Denton's voice said in her mind. Now, sorry to interrupt your daydreams, but can I ask if you've been paying attention to me?

Marney frowned at him.

Denton, tall and overweight, pushing eighty and nearly always with a cheery expression on his ruddy face, was now giving his protégé a reproachful look.

Usually favouring crumpled three-piece suits, the old empath was dressed in heavy fatigues, a jumper that struggled to confine his generous paunch, and a travelling cloak of green wool that covered the rucksack on his back. He carried no weapons – unlike Marney, who wore a baldric of twelve slim, silver throwing daggers beneath her cloak – and his footwear was a sturdy and sensible pair of hiking boots. However, his headwear gave him a slightly ridiculous look: a floppy, wide-brimmed hat that had seen better days, but one that Denton refused to be seen without.

Well? his voice urged in Marney's head.

Oh! Right. Marney shook herself and spoke aloud. 'Yes, Denton, I was listening. No one knows what we're doing. Say nothing about the mission, not even to Gideon.'

'Or Van Bam,' Denton stressed knowingly.

'Okay. I get it.'

'I hope so, Marney, because the House we're travelling to is ... well, a little fabled, to say the least.'

Denton impressed an emotion upon Marney then, a light sense of anxiety that was enough to lessen her awe of the Trees of the Many Queen.

She swallowed. 'The Library of Glass and Mirrors,' she whispered.

'Exactly,' Denton said. 'And I hope that you appreciate just what a perilous place it is, Marney.'

She did. The Library of Glass and Mirrors was indeed a fabled House, a myth, a fairy tale, or so most humans and Aelfir would claim. The legends said its librarians kept the records of what was, what is, and what would be. The complete histories of the past, present and future – how could such a library exist?

Yet it did – somewhere out there, its dangerous doorway hidden among the Houses of the Aelfir. The Thaumaturgists knew it was real, had always known, but they feared the Library of Glass and Mirrors and the impossible histories it kept. The Thaumaturgists encouraged the myths and disbelief in its existence. Yet now Lady Amilee had sent the two empaths on a secret mission to find the Library. But to reach it, Marney and Denton first had to cross many Houses, many of which were embroiled in the war against Spiral and the Genii.

'Ah, here comes our liaison,' Denton said, and he pointed into the trees to Marney's left.

Marney struggled to see her at first. She began as a shadow of movement that emerged from the treeline, and only then did Marney realise that the stranger's cloak must have been charmed to blend in with the colours of the forest. The stranger carried a quiver of arrows on her back and an unstrung bow in her hand. She stopped on the dirt road and pulled back her hood, revealing unruly brown hair and a grubby Aelfirian face with large, keen eyes.

'Greetings,' Denton called. Remember, Marney, say nothing of our mission, he added mentally.

The Aelf approached them. Her clothes matched the design of her cloak, and there was a curved dagger tucked into her belt. Instinctively, Marney reached out with her empathic magic, reading the Aelf's persona. What returned were the emotions of a trustworthy woman, stern yet kind, but nobody's fool.

'And greetings to you,' she said. Her voice was gruff, it seemed to belong in a forest. She appeared to size up Marney, and then Denton. 'Can I be of assistance?'

Denton smiled. 'We're looking to procure passage through your wonderful House. Perhaps you've been expecting us?'

'Perhaps I have. Do you carry proper permission for this passage, sir?'

'Indeed I do.' Denton pulled out a black leather wallet, which he flipped open to show the Aelf a square plate of a strange grey metal that seemed both solid and liquid.

The Aelf stared at the plate for a moment, and then reached out to press a finger against it. Immediately, the strange metal began to change, bubbling and sinking into grooves that quickly depicted the shape of a diamond set within a circle – the sigil of Lady Amilee the Skywatcher.

With a satisfied nod, the Aelf gestured to the treeline on both sides of the dirt road. Marney heard undergrowth rustling and twigs snapping, and she caught the shadowy movements of the Aelfir who had just been ordered to withdraw from the human visitors. But she had sensed no emotions, detected no other presences in the vicinity. How many arrows had there been aimed at the empaths?

'It's wise to remain cautious at such times,' the Aelf said, giving Marney a relaxed smile. 'Welcome to the Trees of the Many Queen. I'm to be your guide. I've been ordered to lead you to your next destination.'

'That is gracious of you,' said Denton, sliding the wallet back into a leg-pocket of his fatigues.

'My pleasure.' The Aelf raised a hand as Marney made to introduce herself. 'Forgive me, miss – best not speak of names. I've been told to ask nothing of you or your plans.' She nodded meaningfully at each empath in turn. 'Now, there's fair way to go, and nightfall's not far off. We should be leaving.'

Without further word, she turned and led the empaths from the dirt road and into the forest.

Nightfall? Marney thought to Denton. It was morning when we left the Labyrinth.

Denton smiled at her as they entered the trees. Time doesn't run evenly through the Houses, Marney. I'd have thought your books would've taught you that.

Marney smiled back at him. Well, a wise old man once told me there's a big difference between knowing a thing and experiencing it.

Ah! Denton's chuckle was light in her head. That must've been a very wise old man indeed.