This presents a before and after look at one teen boy, Mac, who is molested by his doctor. That might be a spoiler of sorts, because mostly the book about his behavior - in the Before, he is interested in a girl and spends time baby-sitting his little brothers, and in the After, you see him punching his best friend, growing distant from his girlfriend, and being mean to his brothers. The mystery is what happened to change this...
I have read both the hardcover and paperback versions of this novel, and I've read this book more than three times. I'm not sure why I liked it so much as a teen (I have not re-read as an adult). I liked Mac as a narrator, and I grew to like him in the first half and so I had concern for him in the second half of the book. Maybe I had a thing for troubled boys, as I also really liked and often re-read the book A Solitary Blue by Cynthia Voigt.