Down Among the Sticks and Bones by Seanan McGuire, 187 pages
In this companion to the excellent Every Heart a Doorway, McGuire explores the backstory of the unsettling twins, Jack and Jill, who are raised in the most Stepford way possible until they're 12. That's when a rainy day spent exploring their house finds them walking down a long staircase into another world. That new world is spooky, uncomfortable, and filled with all manner of fearsome monsters. Yet Jack and Jill, in their vastly different ways, come to see it as home. In this short book, McGuire creates a world that is infinitely creepy, yet addictive; when the story ends, it leaves the reader wanting more, despite the creepiness. An excellently woven story.