Harry has become a virtual recluse after the events in ''Grave Peril''. He spends all of his time isolated in his lab, desperately trying to find a cure for his girlfriend's new initiation into vampirehood. But when the White Council of Wizards comes to town to discuss the war Harry started, toads start raining from the sky, and Mab, Queen of the Unseelie fey, drops by his office, Harry has to snap out of his funk. The wizards decide that the best way to end the war is to hand one Harry Dresden, slightly damaged, over to the vampires--unless Harry agrees to take Mab's case. So unless he wants to become a vampire treat, Harry has to act as Winter's emissary, determine who has murdered the mortal champion of Summer, and prove Mab innocent.

Of course, things are never that simple. It turns out that Summer's emissary is Harry's old back-from-the-dead flame, and she is under the same amount of compulsion to prove Mab guilty. With the help of Billy the Werewolf, Lt. Karrin Murphy, and Toot the pizza-obsessed fairy, Harry attempts to question the suspects: the Winter Knight, Maeve the Winter Lady, Aurora the Summer Lady, and the ancient Mothers of Winter and Summer.

All the while, he is distracted by various attempts on his life by a gun-for-hire ghoul, an angry ogre, and a chlorofiend (plant monster). He also takes on an investigation for a bunch of changelings who are worried about the disappearance of their friend, Lily.

! Tropes
* AntiMagic: Ogres repel magic [[spoiler: As does Lord Talos in his spell-repelling mail]], and Mother Winter casually knits up a magic capable of undoing any enchantment whatsoever while talking to Harry.
* BatmanGambit: [[spoiler: Aurora sets Harry up to get the Unraveling from Mother Winter, then jumps him and takes it from him in order to turn Lily back from stone and sacrifice her on the Stone Table- which itself was only there because the Queens created its surroundings so that they could fight the war that was ultimately instigated by Aurora.]]
* BloodKnight: Maeve quite enjoys fighting. Just not in fair fights.
* BlueAndOrangeMorality: The Fairies, as usual. Harry speculates it's why [[spoiler: [[StatingTheSimpleSolution Aurora didn't collaborate with Mab on handing the Summer Knight's power to Winter]]- Summer and Winter don't work together, so the idea probably never occurred to her.]]
* BigBad: [[spoiler: Aurora, the Summer Lady.]]
* CombatPragmatist: During the final battle, Maeve claims she didn't help earlier because that would be a fair fight, which she avoids.
* CrapsackWorld/DeathWorld: Earth if either of the Courts becomes more powerful than the other.
* DealWithTheDevil: Harry inadvertantly did this with Mab, as Mab bought his service from Lea. Elaine also did this with Aurora, who hid her away from the White Council and Harry.
* DeathOfAThousandCuts: This combined with ColdIron brings [[spoiler: Aurora]] down. Harry arms Toot-Toot and the rest of the little folk with steel box knives, and sets them loose on [[spoiler: her]].
* FamousLastWords: "I don't understand" - [[spoiler: Aurora]]
* EvilPlan: [[spoiler: Aurora's was to give Winter the power of the Summer Knight so that they'd win.]]
* GodsHandsAreTied: The Mothers cannot interfere with the lesser Queens.
* KingmakerScenario: [[spoiler: Aurora can't win the war herself, but she can tip the balance of power with the Summer Knight's mantle.]]
* PersonalConflict: Elaine, Harry's once girlfriend who betrayed and tried to help his old master enthrall him, is back in his life (though she claims that she was under mind control when she did so).
* PsychopathicManchild: Maeve.
* {{Sidekick}}s: Billy the Werewolf, Lt. Karrin Murphy
* SlippySlideyIceWorld: Winter winning would create a new ice age.
* SpannerInTheWorks: [[spoiler: Elaine has to work with Aurora to pay off a debt, but allows Harry to escape and later keeps Aurora's poisonous thorns away from him, allowing to reach her and stop her.]]
* LesserOfTwoEvils : Lea, Harry's incredibly creepy [[OurFairiesAreDifferent fairy]] [[FairyGodmother godmother]], who spent most of the last book trying to turn him into a dog.
* TheReveal: [[spoiler: Lloyd Slate killed Ronald Ruel, under Aurora's orders.]]
* TakenForGranite: [[spoiler: This was how Aurora hid the power of the Summer Knight- she gave it to the changeling Lily and turned her to stone, rendering the power unusable until the enchantment was broken.]]
* TheVamp: Maeve again.