Greg Lademar is an ordinary and average Army veteran who has settled down with his job as an accountant and his lingering PTSD. He lives a quiet life as a single man, alone on the former blueberry farm he bought from his parents after they retired to Orlando. When a friend who works with animal control asks him to foster Parker, a severely injured dog who has just been rescued from an abusive home, the last thing Greg expects is to be dragged into the mysterious world of the Guardsmen — the bonded pairs of humans and their weredogs, known as Protectors, who are literally the stuff of myths and legends.

Greg's life is turned upside down by unexpected events involving Parker and the strange Guardsmen pair Marcus and Alex Stephanek, but far more dangerous to him is the man who used to own Parker and holds a grudge for having "his" dog taken from him. A game of cat and mouse ensues, with more on the line than even Greg ever thought possible: his life, and the life of Parker, who has become more important to him than Greg ever imagined a rescue dog could be.