Beyond the cats, the regular grid of library shelves stretched out into infinity under the great dome with its obsidian markers. Alice set out down one of the aisles, trailing a cloud of disturbed dust. She didn’t pay much attention to where she was going. One of the lessons she’d learned in the past six months was that landmarks and directions inside the library meant very little; you generally ended up where Ending wanted you to, no matter what direction you walked in.

This morning, that meant checking on the acorns before reporting for duty to Mr. Wurms. Alice was not surprised to find herself quickly leaving the tame, organized shelves behind and passing into the wild library that lived behind them. Here the shelves were arranged in clusters, squares and rings and pentagons, and were mostly empty. Strange noises and even smells leaked out of the gaps between them—the clatter of metal, the cheer of a crowd, the scent of roasting meat.

Inside each cluster was a book, or a set of books that shared similar characteristics. Portal-books and prison-books were not like ordinary volumes or the tomes in which Alice founds fragments of magic for Geryon to extract. They were nothing but magic, and—under a Reader’s gaze—they were a pathway between one place and another, one world and another. Left alone, they leaked. Part of Ending’s job as guardian of the library was to arrange these clusters of shelves that in some way kept the books contained and prevented their inhabitants from wandering about.

The inside of each cluster tended to reflect the environment on the other side of the portal. They were like little worlds unto themselves, usually much larger on the inside than they looked from the outside, although mere spatial impossibilities had ceased to really surprise Alice. She found the cluster she was looking for—it was marked on the outside with a complicated rune, but she could smell the rich, wet scent of it yards away in any case—and squeezed herself into a gap between the shelves. Though it looked like it was only a few inches wide, she fit easily.

Inside, the backs of the shelves resembled a ring of stone monoliths surrounding a clearing a couple of hundred yards across. About half of it was occupied by a pond, and an enormous waterfall poured into it, filling the air with its splash and roar. Around the edges of the pond, jungle trees grew dense and thick, wound round with hanging vines and lianas. Huge, thick green leaves hung everywhere, dripping with moisture, and interwoven with sprays of tiny, wildly colored flowers, like miniature fireworks. It was hot enough that Alice started to sweat almost immediately.