Changes

Changes focuses on the three tumultuous days of many changes that occur in Harry Dresden's life after learning that he and Susan Rodriguez have a daughter. Margaret "Maggie" Dresden (named for Harry's mother) was born after their romantic interlude in Death Masks. Susan had hidden knowledge of the child from Dresden for the child's safety, not only because of his list of enemies, but hers as well. She also cites his own dangerous lifestyle and lack of ability to provide a stable home as part of her reasons.
Over the course of Harry's attempt to rescue his daughter, his office, home, and car are destroyed. In order to heal his body and save Maggie after suffering various injuries, including a possible broken back, he accepts Queen Mab's ongoing offer to become the Winter Knight, but only if he is allowed to save Maggie first. He finds out that his mentor, Ebenezar, is also his maternal grandfather, knowledge that was kept hidden from him for many of the same reasons he is now striving to keep Maggie's existence a secret.
Along with the major personal changes in Harry's life, this book marks a major story change as well. At the book's climax, an unholy ritual to sacrifice Maggie and thus kill her entire bloodline (Harry, Thomas, Susan, and the recently revealed Ebenezar) backfires on the Red Court. After Martin reveals he has been a traitor to the Fellowship of St. Giles for over 100 years, an enraged Susan attacks him just as Harry soulgazes him. From the soulgaze, he realizes that all of Martin's actions have been to ensure that Harry would be there to confront the Red King and have a chance to destroy the Red Court once and for all. Susan kills Martin and drinks his lifeblood, turning herself into a full-fledged vampire (and thus becomes the youngest of all the Red Court). Harry then kills her to complete the ritual, destroying every Red Court Vampire in existence due to their shared bloodline via the Red King.
Changes ends with Harry apparently dying after being shot leaving his brother's boat (the Water Beetle). He had been preparing for an apparent romantic interlude with Karrin Murphy, who is suffering depression and despondency after learning her job as a police officer will be lost from manipulation by outside parties. Harry remarks that he sees a white light, but that it is not peace, instead a train coming for him, even as he hears the repeat of the Death Curse afflicting him ("Die Alone!") and a "Hush now" from an unknown, but familiar to him, female voice.