Delightfully creepy

It's difficult to describe The Wikkeling by Steven Arntson, but it's awesome!  Henrietta lives in a dystopian city called the Addition.  It's way over-protective of its children (the school bus has mandatory lap belts, shoulder belts, and head belts), car horns blare out Honk Ads ("EDIBLE CLEANTASTE CORN SOAP!!"), and almost all the houses are identical, with a patch of green plastic grass out front.  But Henrietta lives in an old house, with a steep roof and an attic.  She discovers a wounded cat up there, and while caring for it, notices windows which  have never been visible from the street.  And when she looks out the windows, she sees the past!  Henrietta takes her two friends up there, and together they try to figure out many things: why does time seem to stand still when they're in the attic?  What is the cause of the headaches only those three get?  How are they linked to the scary yellow figure that only they can see?  I wouldn't call this book scary, but it's definitely creepy in a really, really good way.