Due to some fluke of her breeding, Sin is the first--and only--Seminus demon to be born female. Like her brother, Lore, she has lead a harsh life full of hurt, sorrow, and loneliness. Her mother didn't love her, her grandparents died, and her brother left, convincing Sin that eventually, everyone leaves. Stealing herself against all emotions, she never lets anyone get close enough to hurt her. After falling victim to the demon world and her Seminus blood, Sin eventually finds herself playing the role of assassin. And she's good. Maybe too good. 
 Part of an anomaly, Sin is capable of infecting her victims with a disease unique to them, but after a hit gone bad, Sin finds out that the infection she spread has gone out of control, and now the entire warg population is in danger of extinction. Now, the Council is out to get her, her assassins want her dead, and the world is about to go to pot. 
 Con, a half-vampire, half-werewolf, had been put in a precarious situation. After a recent hook-up with Sin, he finds out that she is not only the sister to some of the most powerful Seminus demons he knows, but is also the cause of the deadly plague wiping out his friends and family. When he is charged with bringing her in for judgement, and probable execution, he has a decision to make: bring her in, or keep her safe until a cure can be found. 
 I'm not going to say this was my favorite of the Demonica series, but I will say it was pretty darn lovely. I enjoyed the steamy connection between Con and Sin, and I even enjoyed the detailed explanations about the virus and the warg communities. I think what I liked the most was the raw, intensely honest emotion that was wrung from these characters. It can be difficult to capture emotion in a character, but the author did exactly that--in spades. Overall, the romance that slowly developed was believable and heartwarming, but certain aspects of the story caught my attention even more. Example: I really liked the side story of Luc and Kar. I wanted so much more of that, to delve deeper into their history, but it was pretty well wrapped up, so I am sure that will never happen. Also I really liked the appearance of the Horsemen. Since I was first introduced to Ione's stories via the Horsemen series, I am well-acquainted with them, and I feel like they added a great twist to the story and direction for the sister series, which is already well underway. 
 I haven't looked into whether or not there will be more to the Demonica series, but I really, really hope there will be. I love all the characters and their history, and even though I will be fine following on the heels of those delicious horsemen, I want to see more of Sin, Eidolon, Lore, and, especially, Wraith.