This book worth staying the whole night reading it until dawn. Lol. 
 There's two major part of the story, one is between Charles and Anna, and another was a serial killer on the loose. 
 The story started with Anna arguing with Bran about him still letting Charles out to do the 'errands' that Anna frizzled up and started worrying about Charles increasing state of depression. Apparently, everyone was not worried that Charles was turning to the darkside except Anna who saw it was happening to their mating bonds. In other part of the country, Adam was busy with a newly injured Mercy (which I haven't get to book three yet and shall remedy that) when FBI called up to him for consultation to a serial killing case with an eight year old boy found raped, mutilated and murdered. 
 Out of desperation, being an Omega wolf, Anna decided that she was the right PR for the job and dragged her troubled mate to Boston where she met with FBI agents, notably Leslie, Cantrips and Homeland Security where they discussed the serial killing links from series of victimological unrelated murders which they found all of the victims were linked for being half-blooded supernaturals. A couple of hours later, a young half-fae woman was kidnapped from her home when things starting to get sinister. 
 I do stay up until 5am to finish this from 2am reading half of the book. The story is very Criminal Mind version Supernatural and was easy for me to follow. The pieces of the puzzle rearranged and blended well enough to be a proper procedural-mystery book. I'm like Anna in this case, I suck it up from the TVs. Leslie is like Anna Torv if you think about it. 
 I shall be waiting patiently for the next book. Its very well written and unpredictable of sorts. The ending is classic. I would have said more but I wouldn't want to spoil it. Suffice to say, someone should make a proper FOX tv series for this.