But Arpix, stepping into thin air and elevating himself to Evar’s height, answered the question. “It’s a state of mind. I think it’s a visual metaphor for ascent of some kind.”

“Huh?” Clovis tested the air around Arpix with her foot, finding nothing.

“Up here.” Arpix turned slowly and touched between his eyes. “Look at me.” He took both Clovis’s hands in his. “You need to want to follow me.”

“I guess hunting is a type of following.” Clovis grinned.

As Arpix climbed the invisible stairway backwards, leading Clovis up, it seemed to Evar not dissimilar to the way that Livira had taught him to fly. Arpix appeared most confident as a teacher, and Clovis, eager to learn, rose from the ground, her steps mirroring his.

With an effort, Evar calmed himself, focused only on the next layer of the Exchange, until it seemed almost solid, and without looking at his feet, began to climb the stairs that weren’t there.

“Well, this isn’t right,” Starval complained behind them. “I’m the one who’s great at climbing. Never met anything I can’t climb, except the library walls. And I still haven’t. There’s not a damn thing heretoclimb.”

“Just pretend there is,” Evar said. “If growing up in a library doesn’t equip you for pretending then I don’t know what would.”

Starval raised a foot and with great deliberation set it back down, passing through any invisible step that might be there on the way. “Damn it!”

Mayland looked back. “You know why you’re still down there, brother. It’s a matter of commitment. You know what I’ve asked of you and why it must be done. If you have the courage of your convictions, step up.”

Starval locked eyes with Mayland, a bleak stare. It had in it something of the look his eyes used to hold on emerging from the Mechanism after a long day of imaginary death dealing, plying the trade for which he’d trained so long. “Damn you, Mayland.” Once more he took the step, and this time, he rose.

They climbed throughseveral dozen layers before Mayland halted, jumped down, and set his feet squarely on grass which in that moment became as real as the grass they’d left behind. The trees, the pools—it was the Exchange as Evar had always known it, but with a greyer sky and a cool whisper of a breeze. The malady that had changed the Exchange they left behind was present in this alternative but to a lesser extent.

“So, all we need to do is find this king and take the book off him?” Clovis looked around her. “And everything can go back to how it was?”

“It’s easier to poison a well than purify it.” Starval patted the nearest tree as if uncertain whether it could be trusted.

“I don’t intend for anything to go back to how it was, sister.” Mayland narrowed his eyes. “We’re here because I don’t trust that venal human to finish the job Evar and Livira started and Arpix helped along recently in grand style.”

“How do you even know about Oanold?” Arpix asked, still wincing at the praise he’d received for unwittingly destroying the Mechanism.

Mayland started a slow walk along the nearest timeline, pausing by each pool. “Starval and I have done quite a bit of spying. Once I realised what Evar and his human were making, I needed to understand all the factors at play so I could manipulate events should they go off course.”

“I don’t understand why you even needed us,” Evar growled. “Couldn’t you just write your own book or whatever?”

“It’s a complicated knot you two tied through time. It’s written into our lives. Fated, if you like. Something I could take advantage of once I became aware of its existence, but not a thing I could craft myself. In any event, completing a work like this needs vision. And Arpix’s little king can’t see past his own greed. Besides, given the manner of his arrival and the level of his ignorance, he may well have spread himself across dozens of alternatives. This one is just my best bet. And in each alternative he will, most likely, have fallen into himself. We’re not looking for Arpix’s Oanold. We’re looking for whatever he was in this alternative.” Mayland pointed at the pool just ahead of them. “Let’s just hope he didn’t land hard enough to scatter, or if he did, that at least the book will be here.”

And then, as if what he’d said made sense or was in any way enough to equip them for what lay ahead, Mayland reached out an open hand to Starval and to Clovis. Evar took Starval’s hand and Arpix Clovis’s.

“Ready?”

Evar swallowed his “no.” Livira was out there, and her book was the key he needed to unlock whatever doors stood between them.

“How do we stop ourselves from doing the same thing as Oanold?” Arpix asked. “The fragmenting thing, and the falling-into-ourselves thing. We’re not going to be any use if we forget who we are and why we’re there.”

“Focus on who you are and why you’re going,” Mayland said. “If you smear out across possibilities, that’s not such a problem. You can search them too. Staying yourself is the key. Using the Exchange should ensure that, but these are strange days. Any other questions?” He looked left then right.

Receiving no answer from any of them, Mayland stepped forward, and the waters took them.

“Where are we?”A twisting jolting rush had filled Evar’s eyes and mind with unimaginable colour, only to leave him stumbling into a dimly lit somewhere, blinking to clear his vision of shades he would never be able to remember.

“It looks like a rather poor copy of the library.” Starval’s whisper reminded Evar that stealth might be a sensible precaution.

They were in a chamber whose ceiling was almost low enough to touch and whose walls were scarcely more than ten yards apart. The bookshelves that filled the place were so short that simply by lifting up on his toes Evar could peer across their tops. Large windows at the front of the chamber should have filled the place with light, but the space beyond them was grey and featureless.

Evar seemed to have emerged from a portal rather than a pool, a shimmering circle of light drawn on the chamber’s rear wall. “Where’s Arpix?” Evar spun around. “Where’s Clovis? Where in all the hells is Mayland, come to that?”

“I lost hold of them.” Starval moved out slowly among the shelves. “Hopefully Mayland’s nearby.”