Harry is bailed out by his girlfriend Susan Rodriguez, then receives an official invitation to represent the White Council at a Red Court vampire party.

While trying to rescue a young seer, Lydia, Harry is attacked by two Red Court vampires (Kyle and Kelly Hamilton).

He has a flashback dream in which he recalls events three or four months prior, when Special Investigations, Michael, and he went to capture Leonid Kravos, a sorcerer, cult leader and serial killer.

When Dresden awakens, he discovers that the Nightmare's dream attack was both real and powerful, draining Harry of much of his magic.

Dresden (followed closely by Michael) tracks down the Nightmare to Graceland Cemetery, but is losing his struggle with it when the Leanansidhe appears again.

Susan, who had tried calling Dresden while he was performing the exorcism, arrives with a forged invitation, unwittingly forsaking the pledge of safe conduct extended to legitimate invitees.

Harry swallows a goblet of wine spiked with Red Court vampire saliva (which is both narcotic and addictive, and which he had been exposed to the day before).

As Harry and Michael try to safely extricate Susan from the party, they encounter Mavra, who is both a noble from another vampire Court and the sorceress controlling the Nightmare.

When he awakens, Thomas arrives at Dresden's apartment, offering Michael Amoracchius in exchange for an alliance to rescue both Susan and Justine.

They meet the Leanansidhe on the way, but Thomas and Michael distract her long enough for Dresden to eat a poisonous mushroom which will kill him if he does not get treatment as soon as possible.

Susan rejects Harry's marriage proposal and leaves Chicago, knowing that her half-vampiric condition would eventually compel her to kill him, in any moment of weakness.

Kristine Huntley, writing for Booklist called Dresden "...a likable protagonist with more than his share of troubles, and Grave Peril will keep readers turning the pages to find out how he overcomes them".

[3] Publishers Weekly wrote: "Despite this narrow [first person] point of view, Butcher successfully lends human dimensions to vampires and spirits through his vivid descriptions and colloquial dialogue.