Normally happy and well-adjusted, Sophie Duguet doesn't understand what's happening to her: she has begun losing things, from her recently delivered mail to the car she parked the night before. She is constantly forgetting things she's said and done, too ... only to be reminded of them by her acquaintances. She's even detained by the police for shoplifting--a crime she has no memory whatsoever of having committed. But this is just the beginning. As she slowly sinks deeper into dementia, things go from troubling to alarming. Soon she finds herself connected to the deaths of several people around her: a neighbor boy she is babysitting is murdered while in her care; a stranger seeks shelter with her and winds up dead; and finally, her employer is killed in a way that suggests she was responsible. And she doesn't remember a thing about any of it. To escape the nightmare, a confused and horrified Sophie changes her name and relocates, hoping to outrun the demons that have begun to plague her. But this may not be enough to stop the evil that has poisoned her life and begun to claim the lives of everyone around her.