Kate and the porcupine walked back along the swaying, rumbling, chuff-chuff ing train, through the sleeper car, then the dining car, then the kitchen car, then the other kitchen car, then the other dining car. Kate was starting to get a little nervous when they finally opened the door to the library car.

All credit to Uncle Herbert: It was not a disappointment.

This was the extra-tall indigo-colored car she’d seen earlier. Every square inch of its walls was crammed with books—the shelves ran all the way up to the ceiling, which must have been fifteen feet high. There were even bookshelves over the doors and windows. The floor was covered in thick red oriental rugs, and there were two overstuffed leather armchairs and a big, long, comfy couch. It even smelled like a library.

OMG, Kate thought. I am awesome at inventing train cars!

The porcupine looked around.

“It’ll do.”

He climbed up onto one of the armchairs, settled down, and closed his eyes.

“I’m mostly nocturnal,” he explained.

Then he went to sleep.

Kate walked the length of the library car, running her fingertips over the spines of the books. Each bookshelf had a wooden bar along it to keep the books from falling off when the train swayed; you could unlatch it and swing it open to get a book out. It was exactly what she’d imagined, only more so.

She skimmed a few titles. It was an incredibly random bunch of books: fat, dignified old hardcovers; big, skinny picture books; cheap paperbacks with spines so worn that you couldn’t read the titles anymore. There were guides to identifying moths in distant parts of the world, and multivolume sets of the complete letters of people with long, unpronounceable names, and romance novels with heroines spilling out of their gowns and heroes busting out of their shirts, and thrillers and horror stories with creepy one-word titles like The Trees and The Leaves, and important grown-up novels that she mentally reminded herself to skim later for interesting and/or bad words.

And every once in a while, like a friendly face in a crowd, there were the kinds of books that Kate liked, which fell into two general categories: books about science and books about ordinary people who find out that magic is real.

Kate took down a promising-looking book from the second category and sat on the couch with it. Twenty minutes later, when the hero of the novel was just at the point of discovering that the horrible, abusive private school he’d been transferred to after the unexplained deaths of his parents had a secret school underneath it, accessible via the locker of that one kid who had mysteriously disappeared last year, something alerted her to the fact that she was being watched.