After attending a Winter Ball at the court of Queen Arden, Toby is looking forward to a good morning's sleep, but she is shockingly awakened by the arrival of an unwanted guest - Duke Sylvester's brother, Simon Torquill, the villain who transformed her into a fish back at the beginning of this whole saga. Besides his unwelcome presence, he brings unwelcome news, which will shock Toby out of her slumbers and set her on a path towards...vengeance?
There's just no good way to talk about this story without spoilers, so be warned.
Simon was once married to Toby's mother, Amandine, one of Oberon's Firstborn, and Toby actually has an older sister, August, who disappeared long ago. Many of the people around her, whom she counted as friends, knew of this but have never seen fit to tell her. Simon claims to have been under a geas when he attacked Toby; one that he was able to twist sufficiently to merely transform her rather than murdering her as he was supposed to do. Of course, Toby doesn't believe his story at first.
When Toby goes to see the Sea Witch to find out if what Simon has told her is true, it turns out that she is also under the same geas, and cannot tell Toby what she wants to know about the identity of her true enemy. When the Luidaeg manages to slip the geas just a little, the person who put it on her comes and wreaks vengeance on her body, leaving her to die as soon as Toby and Tybalt leave. Toby realizes later what has happened, and uses some of her new found blood powers to raise the Sea Witch back from death.
Simon turns up again on Toby's front porch and delivers a cryptic warning in a bouquet of roses. Toby and Tybalt decipher it enough to believe there is a threat to Goldengreen, and take the Shadow Roads to get there. A powerful ward dumps them out of the roads and into the ocean in the San Francisco Bay, and the Cat Lord and Quentin are separated from Toby - she thinks them dead. Dianda shows up in the nick of time to pull Toby out of the water, and requests her help getting into Goldengreen, where her son, Dean, now rules.
When October finally reaches the heart of the knowe, she finds to her great shock that it has been repossessed by Evening Winterrose, former Countesss of Goldengreen, whose "murder" Toby was bound to investigate, several episodes back. She has returned from the dead, with mischief on her mind - or perhaps even her apparent death was part of her long term plan. Evening makes a grand exit from the scene, and Toby begins to deal with her grief over the loss of Quentin and Tybalt. When Tybalt's nephew and heir, Raj, shows up, she cannot bear to return to the Court of Cats, until he tells her that Tybalt is alive, and dragged Quentin out of the water, as well.
Reviewing the situation, our heroes come to the conclusion that Winterrose was behind the whole plot from the beginning, and was the one who had Duke Sylvester's wife and daughter kidnapped, Toby neutralized, and set the geas on Simon and the Luidaeg. When she turns up at Shadowed Hills and charms (in the magical sense) most of the inhabitants, including Sylvester, Toby decides she has to get to the knowe and figure out what the arch villainess is up to. She and the boys sneak in, make contact with Etienne and his family, and Toby visits the Duchess, Luna.
Luna won't answer her questions unless Toby sorts out Rayseline's blood first (Rayseline is mixed heritage, and Luna believes it is slowing her awakening from elf-shot slumber), so Toby, who hasn't even slowed down to eat or sleep through all of this, uses her blood powers to change Rayseline to Daoine Sidhe at last...then collapses. Fortunately Tybalt gets the information they want from Luna before carrying Toby back to the Court of the Cats, where Toby finally gets a bit of rest and a chicken dinner.
Evening Winterrose is actually the head of the Daoine Sidhe line, their Firstborn, daughter of Titania. No member of that bloodline is able to resist her compulsions, and any other Sidhe who is bound by their blood not to harm the descendants of Titania are also at a serious disadvantage dealing with her. One odd little bit of information that may become relevant later is that she was the one responsible for Quentin's fostering with Shadowed Hills.
Simon again visits Toby's house and Toby reads his memories by her blood magic, discovering a few new things that shed light on his motivations. Unfortunately, he can't help betraying her to Evening, and she ends up rescued by the Luidaeg, who accompanies her and Tybalt to the "final" confrontation which puts an end to the Winterrose threat...for a time.
A good tale, which wrapped up a little too handily - as if McGuire had a word count contract to meet and had to squeeze it in suddenly. Looks like at least two more books are planned in the series, so there's some more good adventure to look forward to.