This is book 4 in the series. Again, it probably would mostly make sense on its own, but certainly would be clearer if one read the series in order.
Kitty gets fully drawn into the supernatural politics that she ran away from in the first book. This story is really more about the vampires than the werewolves, and we get a lot more examination of the vampire society, although we still won't understand everything of course. We also learn that there's another price for lycanthropy which takes a big emotional toll. And we get to wrestle with an ethical issue on the side which could undermine Vaughn's whole world if one thinks about it too much, so it's best we don't. 7 out of 10.
**** MINI PLOT SUMMARY -- SPOILERS ****
I'm getting events here out of order, but hopefully I'll be remembering the main things that happen.
Apparent vampire victims have been turning up in Denver, bringing Arturo's leadership into question. Rick is going to take over, and he tries to recruit Kitty to take out Carl. Kitty isn't willing to get involved, but then Kitty's mom gets cancer, so Kitty has to go back to Denver to be with her. Mercedes Cook is a very powerful vampire and a meddling bitch playing the Great Game; she uses Kitty's show as a forum to "come out" (she's had a long and successful career as a musical actress and singer). Most of Rick's group gets trashed. It turns out that Dack, the were African wild dog, is actually Mercedes' agent and ratted Rick out. Kitty rescues Carl's new omega werewolf, only to lose her when the girl calls Carl from the airport and gets talked into staying; Carl kills her. Kitty resolves to take Carl and Meg out, recruits some of the decent underlings of the pack, and wins the fight. Arturo tries to use Kitty's mom as a hostage, but Kitty takes the damage of holding a silver cross to drive him away. Rick ends up able to catch Arturo in a one on one and proves that he (Rick) is the more powerful vampire after all.
Kitty has a miscarriage, and discovers that werewolves can't have children -- shifting always results in miscarriage.
When Kitty's mom is diagnosed with cancer, Kitty realizes that she could save her by turning her into a werewolf. (Werewolves don't have mundane health problems like cancer.) Mom refuses the offer, but it brings up the uncomfortable question: if being turned into a werewolf (or vampire?) could save anyone with an unpleasant fatal condition, how long can it be before werewolves are a major fraction of society rather than a tiny fringe? And how could society deal with having many millions of werewolves running around? Because even if Kitty is ethical enough to ask Mom if she'd rather be a werewolf and die of cancer, and Mom is committed enough to being human that she says no, I think an awful lot of people who had major health problems and access to a werewolf would choose to be bitten, and it would only take a few werewolves who were arrogant enough to take matters into their own hands to create a heck of a lot of wolves. (One werewolf could infect a whole hospital in one rampage, and believe they were doing good.)