Mercy must deal with an unwanted guest - one that brings a threat unlike anything she's ever known. An unexpected phone call heralds a new challenge for Mercy. Her mate Adam's ex-wife is in trouble, on the run from a stalker. Adam isn't the kind of man to turn away a person in need, and Mercy knows it. But with Christy holed up in Adam's house, Mercy can't shake the feeling that something about the situation isn't right. Soon, her suspicions are confirmed when she learns that Christy has the farthest thing from good intentions. She wants Adam back and she's willing to do whatever it takes to make it happen, including turning Adam's pack against Mercy. Mercy isn't about to step down without a fight, but there's a more dangerous threat circling. Christy's stalker is more than a bad man, in fact, he may not be human at all. As the bodies start piling up, Mercy must put her personal troubles aside to face a creature with the power to tear her whole world apart.