Unbeknownst to humans, the werewolves of the world live in tight knit gangs, or "dens", for protection from outsiders - and each other. Every major metropolis has one; to belong to a den is to have a family for eternity. Shaye Cassidy, an unhoused human woman scraping by on the streets of Los Angeles, hasn't had anything close to a family in over ten years. Shaye left her home under a cloud to chase the dream of a new start, a dream that quickly turned into a nightmare; a nightmare that grows even more twisted when Shaye witnesses a werewolf killing a fellow unhoused man. Andy Vasquez is a top member of Sangre Sagrada, second only to the den leader herself. When she tasks him with tracking down a werewolf gone rogue, someone who is killing humans for sport and risking the exposure of their world, Andy dedicates all his resources to the task. He couldn't have predicted that the key to uncovering the identity of the rogue wolf would be a human woman, any more than he could have predicted that he would fall in love with her. Now, Andy must protect Shaye not just from the rogue wolf, but also from those within his den who wish she would disappear. Shaye has her own secrets, however, and in the city of angels, everyone has a devilish side.