"Penance" begins with the murder of schoolgirl Emily on a day when she was out playing with four of her friends. The book then follows each of these friends, showing how the murder impacts their later lives, ending with a perspective from Emily's mother. 
 I found this an entertaining and gripping thriller. It did show the dark side of human nature and of small town life but I never found it especially scary or disturbing. I liked the way each of the girls was given a distinct voice, and although it did feel a little rushed, I was satisfied with the ending.