This book was very unlike the others in the A&O series. I generally like the Mercy books much better, but I found this one quite enjoyable. There's a bit of a cop drama feeling to the story as Charles and Anna pursue a serial killer that has been hunting across the country for multiple decades. 
 We get some more detail on Charles's backstory in this book, a welcome addition to his character development that was somewhat lacking in the previous two. 
 Four stars from me for this latest installment of Alpha & Omega.