I don't quite know whether to simply call The Killing Jar paranormal, or to venture into the horror classification--there are elements that are kind of "Children of the Corn," but while some are grotesque and kind of ghastly, I didn't find the story itself too frightening, except in a few isolated moments.
Kenna has a horrifying event in her past that defines her. Because of a dark power she has trouble controlling, she has strict rules for her life, partially enforced by her mom, but mostly self-generated: She keeps to herself, is careful not to get too emotionally close to anyone, and doesn't touch people. But things are looking up: Her best friend, Blake, enters her in a music contest and her entry is chosen out of thousands.
She's having feelings stronger than friendship for Blake, and wonders if she dares to explore that. But just when she lets down her guard, the past catches up with her, and when the crisis is past, Kenna is living in a commune with a relative she didn't know she had, and trying to decide whether it's ever going to be possible to go home...or if she wants to.
The writing in this is dynamic, the plot moves fast, and we jump into the action from the beginning. The story and events keep the reader intrigued to the very end. Along the way, some of the language--Kenna's descriptions of the ecstatic experience of nature, for instance--is truly beautiful. The one thing I'm going to say, and I can't believe I'm going to say it, is that although I find many YA books too long and wish they had had a more ruthless editor, this book could have used another 100 pages to address the scanty coverage of some things. There were a lot of mysteries that should/could have been discussed, fleshed out, or resolved. Some of the relationships seemed shallow, and I wondered about the inner motivations of the people involved, but there were no explanations. The ending was climactic, but it left so much unexplained that I am inclined to expect a sequel, although none may be forthcoming, because it's not obvious whether it's intended to be a stand-alone or part of a series.
Still, it was an exciting and enjoyable book, and the paranormal element was so unusual and so graphically described that I think it would grab a lot of readers.