Plot summary
As the story begins, Harry is in Arctis Tor where he is nursed back to health by Sarissa, a member of the Winter Court and a servant of Mab, the Winter Queen. His recovery culminates in a Winter Court party, serving both as an introduction of the new Winter Knight and as Harry's surprise birthday party. During the party he is set up by Maeve, the Winter Lady, who sets a number of events in motion in an attempt to kill him. With help from Sarissa and advice from Kris Kringle, he defeats Maeve's minions and asserts himself as the Winter Knight before the entire Winter Court. Mab, quite satisfied at this outcome, gives Harry his first mission as the new Winter Knight: to kill Maeve.
Harry returns to Chicago and consults Bob, to find out how to go about killing an immortal. Bob is initially reluctant to give out such dangerous information, but eventually tells Harry that immortals can be killed during certain conjunctions, such as on Earth on Halloween night, the day after tomorrow. Harry meets up with Molly, who informs him that energy is growing on Demonreach and she thinks it might explode. He travels to the island and speaks to the spirit of Demonreach, learning that the island is a prison which was created by Merlin himself to contain a massive number of various unspeakable supernatural horrors. Because of his connection to the island, he is now the prison's de facto Warden. The island is under attack, and if the attack is not stopped, the prison's fail-safe will trigger, releasing enough magical energy to destroy the prison as well as level a significant portion of the Midwest.
In trying to figure out how to proceed, Harry consults with many magical powers, including Donar Vadderung, Lily, Titania, the Faerie Mothers, and Rashid. Harry learns that Outsiders are constantly attempting to get past the Outer Gates, which are defended by the Winter Fae. He discovers that Outsiders are behind his present troubles, and that an Outsider infiltrator named Nemesis has been behind many challenges faced by Harry and by the world in general for many years. He also figures out that the ritual that will be used to destroy Demonreach will be performed at the island itself at some point in the near future.
While preparing for the assault against the hundreds of Outsiders attacking Demonreach, Harry is chased and attacked by the Wild Hunt. With Karrin Murphy's assistance, he is able to evade the Hunt temporarily, and after shooting the Erlking, he takes command of the Hunt and leads it against the Outsiders. With the reinforcement of the Hunt, Harry is able to disrupt the ritual and repel the Outsider attack.
Harry and his friends head for the top of the island, where they find Lily and Maeve magically assaulting Demonreach. Harry, having determined that Maeve has been corrupted by the Nemesis, attacks Maeve. She defeats him soundly but he is rescued by his friends. Harry, out of options, summons Mab, who appears and confronts Maeve. Maeve refuses to yield to her mother and shoots and kills Lily, and is then shot and killed by Murphy in turn. The mantles of the Summer and Winter Ladies pass respectively to Sarissa and Molly, and Mab departs with both of them to begin training them in their new duties.
Harry decides to remain on the island for the time being so that he can learn more about it and establish a new base of operations, and takes a branch from its oldest oak tree to use in making a new staff.
