From the blurb:
"Ryder Creed rescues abandoned dogs and turns them into heroes. But this time, it's Creed who may need rescuing when a madman leads him and Agent Maggie O'Dell on a gut-wrenching scavenger hunt.
Sixteen years ago, Ryder Creed's sister, Brodie, vanished from an interstate rest stop. She was only eleven and Creed was fourteen. Her disappearance ripped apart his family and has haunted Creed.
Now a former Marine with his own scars, Creed has dedicated his life to his K9 business. He takes discarded and abandoned dogs and trains them for scent detection. Together they search for the lost and the missing. And always, Creed has held onto the hope that one day he might find out what happened to his sister.
A thousand miles away during a police raid, FBI Agent Maggie O'Dell stumbles upon a clue that may explain what happened to Brodie Creed all those years ago. But to find the answers she'll need to make a deal with a madman. And the search that follows will be as agonizing for Creed, as are the answers he discovers."
This is a tightly plotted, wonderfully written novel. I love the search and rescue/cadaver/sniffy dogs that show up in these books. The main characters are also strongly written. There isn't much more to write that isn't in the blurb and that won't be a spoiler. There are no cliff-hangers at the end of these books but some characters reappear frequently and show growth/development so reading the previous 3 books is helpful, but not necessary.