This is book 2.5 in the Alpha and Omega series (it starts with the novella "Alpha and Omega" in On the Prowl, and then goes into Cry Wolf). It's a complete episode, but it would be better to know the characters already.
Reading the first few chapters of this book, I was really in heaven. It seemed so good that I was reluctant to actually read much at a time because it would be over too soon. Then the plot really got rolling, and I couldn't put it down. It actually got just a tiny bit less good; the level of power we were throwing around started to be a tiny bit too much. But we did have an interesting tangle of villains, with some sort of expected, some somewhat surprising, and all really evil. The main characters are strong, wonderful, and heroic, and their relationship is pretty close to the Platonic ideal of love. (Which is not to say they have a Platonic relationship!) It is not that everything is perfect for them, but that they have challenges and are able to meet them.
I have a little trouble rating these books; given the depth of my adoration for werewolves, I'm going to give any werewolf book that doesn't just plain suck a good rating, and Briggs definitely Does Not Suck. I reserve 10 for books that I find no room for complaint at all, which means that this one gets another 9 out of 10 (because we get just a little too close to god-level to be perfect).
**** PLOT SUMMARY -- MASSIVE SPOILERS ****
Bran is putting together a meeting with the leaders of Europe's werewolves, because he's getting ready to go public and wants to help them mitigate the problems they will have. He will not let them veto his position; he's been blackmailed enough that he's convinced that the secret can't hold, and he intends to have it out on his terms. Charles is in a foul mood because he has a premonition that if Bran goes to the meeting Something Bad will happen, but to his surprise, Bran is actually willing to be persuaded to stay away and let Charles and Anna stand in. We go to Seattle, where the meeting is to be held, and we meet Dana Shea, the Grey Lord who is pledging to keep the peace. Charles and Anna deliver Bran's gift -- a very nice painting of a scene that is obviously significant to Dana. Dana is clearly moved but her reaction is somewhat guarded, and she promises that she will give Bran a gift that touches him as this one does her. A bunch of the werewolves have gotten together -- not according to plan -- at the best barbecue joint in town, and Charles and Anna go there to try to keep a big fight from happening. They meet Jean Chastel, the Beast of Gevaudan (one of the most famous werewolf legends), who shows himself to be every bit as evil and as dangerous as his reputation. Anna starts doing her Omega magic, and Charles pushes her away, because if he calms down faster than Chastel he's going to be toast. Anna manages to figure this out and instead of running away, just goes into the main room and calms the human crowd. Anna goes out shopping with Tim, the Second of the Seattle pack, and Moira, his wife, a blind white witch. They get attacked by a group of vampires who seem to be using werewolf tactics and magic who are trying to snatch Anna, but since they thought that Tim was the only threat in the pack, two of the six vamps die and the others run away. Then they go to a private dinner with Arthur, the chief werewolf of Britain. Arthur's elevator clearly doesn't go all the way to the top; he is convinced that he is the reincarnation of King Arthur, but he insists on believing some of the more modern parts of the legend. Still, he appears to be a good guy, an ally against Chastel (who doesn't really care if the wolves go public, but wants to gum up Bran's helping the Europeans just for the sake of making life suck for the Europeans), and married to a very nice human Omega named Sunny, who is becoming an old woman. (We never actually go into the question of her being turned, unless I missed it, but we have to assume that if she wanted to try it she could.) Then things start to really get hot. Sunny gets killed by the vamps. There is a hunt staged, sort of a team building exercise, and Chastel attacks Anna, only pulling back at the last minute from what looked like it would have been a killing strike. Charles fights him and wins the fight, but despite the blatant provocation, Dana tries to claim that Charles, drawing first blood, broke the peace. Only she failed to notice that the hunt had officially ended first, so werewolf law was in force, not Dana's guarantee of peace for this hunt. Charles ran off before this bit of lawyering, though. Anna found him. Then later that evening, Chastel is found dead and literally butchered into steaks and chops in a scene obviously intended to freak out any humans who saw it. Only whoever did it was just a bit slow to sound the alarm, and the cleanup crew does its magic before the cops come. But Charles' scent had been left at the scene. Anna and Charles were in bed, but the setup is such that if Dana finds out, she will condemn Charles. Anna and Charles go back to bed, and this time Anna wakes up in the back of the vamps' minivan. Charles tracks the van down, running faster in human form than the van can drive in traffic, and he and Anna splatter all but one of the vamps. They start to suspect Arthur and go have a chat with him. Charles picks up a kitchen knife. Arthur confirms to Charles that he's the bad guy. Then he stabs Charles with Excalibur (the real one), but the wound is less serious than Arthur thinks and Charles sandbags him while he calls on pack magic to heal. They have a sword fight with Charles using the replica Excalibur. A swordfight with werewolf strength is tricky, because the wolves are stronger than the weapons, but Charles is a much better swordsman. Unfortunately, the replica sword can't take the punishment and breaks, but it gets Charles close enough to stick the purloined knife into Arthur's neck. Then Dana shows up, and admits, yeah, she broke her word, but since nobody but Charles knows, it'll be OK. And she puts a death curse on Charles -- her return gift to Bran, because, it seems, that the reminder of her lost home was painful, not pleasant, so she'll kill Bran's son to return the favor. Oh, and she'll just reclaim Excalibur, because she's the Lady of the Lake -- that's what was worth breaking her word. Anna, who still has the vamps' broken manacles on, goes to borrow some clothes from the late Sunny, and the corpse rises and delivers some fae juju to Anna: a finding spell that will lead her to Dana, Arthur's (Pendragon) magic dagger, and a summoning of the Wild Hunt. Anna is supposed to be bespelled, but the iron manacles give her some protection, so she figures out what is happening before she gets to Dana. Dana is supposed to kill her but receive the message. Unfortunately, even though she's figured it out, Charles is going to die before they can do anything else, so she goes ahead and confronts Dana. She offers Dana a bargain: if she will release Charles from the curse, Charles and Anna will keep the secret. But Dana is so hot for revenge that she says no. And Anna goes "wrong answer" and pops her with the dagger.
We don't see the official cleanup of the meeting, but with Chastel out of the way, the Europeans will presumably take the help that Bran offered and they were ready to accept when Chastel vetoed it. There are still a couple of minor bad guys around -- the one vamp who escaped, and the witch who gave Arthur the sleep spell. But we've pretty well tied up this book, with the main challenge ahead being able to come up with something that's tough enough to give Charles and Anna a fight.