The novel opens with Dresden still living on the island of Demonreach. He is approached by the entity of the island, informing him that Queen Mab has arrived. Harry meets her at the docks, where she tells him that she has a job for him to do. They make their way to a building owned by Nicodemus Archleone. Dresden learns that the job Mab has in mind for him is to help Nicodemus steal something from the vault of Hades. He argues with Mab over this, but she convinces him to do it by pointing out that once the job is done, he will be permitted to take a shot at Nicodemus. Wary of the potential for betrayal, he enlists the aid of Karrin Murphy to watch his back.
The next morning, Dresden and Murphy arrive at the location of their first meeting with Nicodemus. They observe Binder and a female warlock, Hanna Ascher, arriving at the meeting place. Over the next two days, Harry is given a series of jobs by Nicodemus. First, he must recruit Anna Valmont, the only surviving member of the group of thieves who had stolen the Shroud of Turin in Death Masks. The second is to accompany Diedre and the shape-shifting new addition to the group, Goodman Grey, as they collect a 'sample' from a high-end financial worker. Harry tries to keep the man alive, but ultimately fails when they are attacked by Tessa. In addition to this, Dresden learns that they are after the Holy Grail.
At the third meeting, they realize that they are being spied upon by Butters. Giving chase, Harry manages to keep Binder's henchmen from catching him with the help of Bob. Nicodemus catches up with Dresden, Murphy and Butters on the street in front of Michael Carpenter's house, and a fight ensues. Murphy draws Fidelacchius and seems to be getting the better of Nicodemus, until she is tricked into using the sword to attempt to kill him while defenseless, in violation of the nature of the sword, which results in the sword shattering. Michael then appears, offering to leave his house (which is protected by angels) in exchange for the release of Harry, Karrin and Butters. Nicodemus accepts the deal, but before Michael leaves, Uriel appears, giving him Amoracchius and his own power as an angel. Nicodemus relents and agrees to accept Michael as Harry's replacement for the wounded Murphy.
The new group then set out to pull off the heist. First, they must break into a real world high security vault, owned by John Marcone. Ascher gets them inside the building, while Binder keeps Marcone's men busy outside. Once at the vault, Valmont cracks open the door, and they enter. Despite another attack by Tessa, they make their way into an inner vault owned by Hades, where Dresden opens a Way to the true vault, in the Nevernever. Once there, Nicodemus sacrifices Diedre to gain entrance to the vault, where Dresden has a private conversation (unbeknownst to the others) with Hades himself. Once the grail is in his hands, Nicodemus wastes no time in turning on Dresden and Michael. Hanna Ascher and Genoskwa, an aggressive Bigfoot-like entity, are revealed to be the new hosts for Lasciel, and Ursiel, respectively. Nicodemus orders them and Goodman Grey (who had supposedly killed Valmont) to attack. At this point, Dresden remembers his first stop with Mab after their meeting with Nicodemus, where he had hired Grey to back him up prior to the planning of this mission. Grey turns on Genoskwa/Ursiel, while Dresden kills Ascher/Lasciel and Michael chases off Nicodemus. They then gather up the still-living Valmont and make their escape from the nevernever, but not before Nicodemus escapes and heads for Michael's house. With Binder's help, they get out of Marcone's vault and confront Nicodemus at Michael's home. During the final fight, Butters takes up the broken Fidelacchius, which emits a lightsaber-style blade and chases off Nicodemus again.
Afterwards, the group divide up a backpack full of diamonds Valmont had stolen from Hades' vault. Dresden pays Grey's fee of 1 dollar in cash, and uses Grey's unwanted share of the diamonds to bribe Marcone into forgetting the break-in, then visits Karrin in the hospital where the two share a passionate kiss. Talking with Michael that evening, they reflect over the events of the past few days, leading them to worry about Harry's future as the Winter Knight.
Harry figures out that everyone in the heist was a pawn. The plot was hatched between Mab and Marcone, to avenge themselves on Nicodemus, with the help of Hades. The plot succeeds: Nicodemus loses Deirdre and all his acolytes and his underworld reputation, but of course gains the Holy Grail as Mab had promised.
Plot points introducedEdit
- The Denarians: Harry being forced to work with them is the main plot of the book. Unexpected changes in allegiance take place around them.
- Family ties: Harry's relationship with his daughter Maggie appears to be growing.
- A new love interest: Harry's relationship with Murphy seems to be coming to a head.
- The brain "parasite": Harry learns that the entity in his mind is a new spirit of intellect like Bob, and the offspring of him and Lash.
- The Knights of the Cross: The Knights' ranks grow as a new bearer for Fidelacchius is chosen in the form of Waldo Butters. Also, with the help of the archangel Uriel, Michael Carpenter temporarily comes out of retirement to wield once again Amoracchius but by the end of the book returns to his normal life. He bestows Amoracchius to Harry, who once again becomes the sword's caretaker until such a time as a new Knight is found.
- Molly Carpenter: Harry notices that Molly is becoming more and more the Winter Lady, and possibly less human.
- The Queens of Faerie: In the vault of Hades, there are statues of the triple-goddess Hecate, which Harry recognizes as being the Queens of Faerie. Despite the implied antiquity of the statues, the goddesses depicted appeared to represent the current Fairie Queens - the two Mothers, Mab and Titania, Molly and Sarissa.
- Demonreach: Harry briefly encounters some of the prisoners of the island Demonreach psychically and begins to learn about the inmates in his charge.