An octagon of empty bookshelves stood in front of them. The cracks between them glowed red, and even from here, Alice could feel the heat rolling over her in great waves that ruffled her hair. She dropped her pack and shrugged off her coat, folding it over one arm, and knelt to untie her shoes.

“You’re sure I’m going to need the coat?” she said. But when she straightened up, the labyrinthine’s yellow eyes were nowhere to be seen. Typical.

Alice picked up her pack again and pushed forward, edging gingerly into the crack between two of the shelves. It looked far too tight for her to squeeze all the way through, but somehow never quite narrowed enough to stop her, as though she were shrinking or the bookshelves were growing. She pushed through and emerged onto a wide, flat expanse of jagged black rock.

Her first breath was like being punched in the chest—the air was hot, and reeked of sulfur. She stumbled backward a step and felt a sharp pain in her bare foot. She’d cut it on a shard of black glass, one of thousands that littered the ground. She looked at the shoes in her hand and rolled her eyes. Is this Ending’s idea of a joke?

Alice pulled on the silver Swarm thread at the back of her mind, wrapping it tightly around herself. Her skin toughened, becoming thick and rubbery, and when she stepped forward again, she felt the glass fragments crunch underfoot. The cut still hurt, but it wasn’t bleeding badly, and Alice set her jaw and made her way forward.

At first she wasn’t sure what she was looking at. The backs of the bookshelves were vast, dark monoliths now, soaring into the distance overhead. Black rock mounded into a small hill just ahead. On the other side of the hill, something glowed red-hot.

It wasn’t until the surface of the glowing stuff shifted that Alice understood. The glow came from a lake of lava that filled the other half of the cluster, the hill of black rock pushing out above it like a promontory over the sea. With every step Alice took forward, the heat increased, as though she were climbing into an oven. At the top of the hill, she could see a boulder of the black glass—obsidian, her mind supplied—and atop that boulder, she was certain, there would be a book.

The ground underneath her was getting hot. Alice suddenly understood Ending’s warning; the rubber soles of her shoes surely would have melted by now. Breathing was getting difficult. There was smoke coming off the lava, evil blue-gray stuff that smelled noxious.