This book, as the narrator/protagonist says, is a murder mystery. I'd add that this is a touching and charming story of a family, as observed and described by a fifteen-year-old autistic boy.
I was afraid that I'd find this narrative device to be contrived or too precious, but I was pleasantly surprised to find myself won over by the narrator's attempts to live in his world, when his world is often overwhelming and confusing to him.
When he finds the neighbor's dog dead one night, Christopher is initially accused of killing the dog. Later, when he's exonerated, he sets about solving the mystery himself and, in the process, digs up some more mysteries that end up changing his safe life.
I really enjoyed this book, and found the author's use of the autistic narrator touching and effective. It was a quick read, but definitely worth it.