Once upon a time, there were two little girls who were -- whether they liked it or not -- as different as night and day. Then they found a door. 
 That is the story of "Down Among the Sticks and Bones," a prequel to Seanan McGuire's enchanting "Every Heart A Doorway" that explores the history of Jack and Jill. It doesn't have the wide-ranging imaginative variety of that book, since it follows only one pair of "foundlings" instead of a bunch, but the story itself is a dark little jewel -- a tragic story about what happens to children who are molded into what others want them to be, instead of what they truly are. 
 Jacqueline and Jillian were raised by parents who forced them into particular roles from day one -- Jack was a dainty doll, expected to be quiet and clean all the time, while Jillian was a rough'n'tumble tomboy. That was what their parents wanted, and they would brook no disagreement.... until the day the girls found a door inside an old chest, walked through it, and found themselves on the wild, dangerous Moors under the shadow of a vampire's castle. 
 And the girls are soon split between the vampiric Master and the grim scientist Dr. Bleak. Over the next five years, Jack becomes a sensible, scientifically-minded apprentice in glasses and pants, while Jill becomes the cruel, elegant "daughter" of the Master. And the girls never see each other as they grow more different than ever before... until the day when Jill's jealousy over her sister is stoked, and her desperation to be turned into a vampire reaches a fever pitch. Then nothing will be the same. 
 Everybody who has read "Every Heart A Doorway" knows about what the twins ultimately become, and what happens to them eventually. No spoilers. But "Down Among The Sticks And Bones" fully fleshes out the hints about why they left the Moors behind, and the reason the door appeared for them in the first place. Let's just say that the doors don't appear for children who are happy and fulfilled, and the girls' parents will quickly show why they weren't eager to return to our world. 
 And McGuire paints the Moors with a loving brush, incorporating every creepy gothic trope you can imagine -- a brooding twilit expanse where werewolves roam the mountains, Lovecraftian horrors lurk in the deep, and an elegant vampire in his castle quietly clashes with a mad scientist who resurrects the dead. It's not a particularly inviting place, but dang, it tickles my vintage horror fancy. 
 Her writing is at its most enchanting here, wrapping black ribbons and silk around this eerie setting with her words. Like many a classic writer, McGuire narrates the story as if she's... well, narrating a story, addressing the readers and averting the narrative during a tragic murder. It doesn't have the glittering multifaceted quality of the first book, since we see only two children who went through the same door, but it makes up for this with the sense of tragedy, haunting loss and gothic grandeur. 
 The character development of the characters is a pretty fascinating one, if a bit flawed. We see them essentially trade places, while developing distinct personalities shaped by where they are -- Jack is especially intriguing because the scientific mind and logic we see flowering in her doesn't preclude love, as she falls for a village girl without losing any of her keen intellect. On the other hand, Jillian seemed slightly less three-dimensional; while her obsessive need to have power and parental approval while being sculpted into she wasn't could warp anyone, she seems to go full-on childish evil. 
 While readers of "Every Heart A Doorway" know how the story will ultimately end, "Down Among The Sticks And Bones" is about the journey rather than the destination -- a tragic tale of two sisters separated.