The world Briggs has built is absolutely fantastic and so real! Also, she does not glorify her supernatural characters. Her vampires are scary and unpredictable, their hierarchic rules bind the werewolves, and old-fashioned prejudices and the Fae are not to be trusted. The plot revolves around Mercy being asked by Stefan, her vampire friend, to help him hunt down a vampire/sorcerer in league with a demon and a danger to the people she cares and loves. Even though Mercy feels torn between helping Stefan and perhaps betraying her friends, she can’t refuse someone who has stood by her and helped her in the past.
The world building in this series is phenomenal. Everything just fits perfectly. It seems like each book adds another layer to the whole picture with complete consistency. I love all of the pack politics and learning about how all of these different groups have learned to live with each other.