The book is a two stream story. One stream is about a family who start spying on their son because he's "acting out," while the other focuses on a teacher whose life falls apart when he's rude to a student who wasn't behaving well in class.
I didn't like the book because I found it difficult to believe. I've got kids who are the same age as the son in this book, and while I can understand what they did, I'm not altogether sure I believe or understand the lengths they would go to to spy on him.
If you can believe in a story that shows parents going to extreme lengths to spy on their son, read this book. If you can't, you might want to give this book a miss.