Penitence by Kristin Koval is about a Colorado family torn apart by the killing of their teenage son by their younger daughter, and how they try to survive the aftermath. Penitence, as its title suggests, is about the acts of atoning and forgiving, both yourself and those whose actions have wronged you. In this case, there are layers of guilt going back to earlier generations that ultimately led to the girl’s awful act, including ones involving her parents, Angie and David, as well as Angie’s ex-boyfriend who is recruited by his mother to help defend the girl. Penitence is a sad book, rife with loss, secrets and hidden regrets, and there is a loneliness that pervades it, as the characters retreat into their own lives of sorrow and silence rather than finding comfort with one another. But it is also a thought-provoking, slow burn of a mystery that gets to the heart of why these broken characters acted as they did. There is enough ambiguity here to elevate Penitence beyond the standard mystery, with a lot to think about while reading and beyond.