Ruby’s been fighting vampires since her mother’s death, seeking to climb the ranks of her human compound and to protect the only family she has left, her sister. But when a scavenging mission goes wrong, her sister gets turned into the one thing Ruby has always fought against – a vampire. One that is now the top target of her compound’s security task force.

The only way to bring her sister home safely is to restore her humanity through the compound’s nearly finished vampire cure. Ruby just has to make sure her sister stays hidden and safe long enough to take it. Unfortunately, the one person who can guarantee that safety is the vampire Ruby hates the most – X, who’s responsible for turning her sister.

Reluctantly, she strikes a deal with him: if he’ll keep her sister safe, she’ll help him break into the compound’s lab and save his imprisoned friend. But the alliance isn’t without its problems - X’s charm proves to be as dangerous as his fangs as Ruby can’t seem to decide whether she wants to kill him or kiss him. Not to mention that teaming up with a vampire is treason. Ruby doesn’t just have to watch her back in case X betrays her, but she’ll have to work to keep her new alliance a secret from her own people or risk execution. Trusting the wrong person – vampire or human – will mean the death of both her and her sister.