Thirty years ago, nine-year-old Alice disappeared. Alice’s mother, Mrs. Helen Avery, suspects a self-fulfilling prophecy is at play. The father, a physics professor, searches for answers by conducting research that ventures into parallel universes. The older sister, an author, writes stories that shed light on the family’s past interactions. Two investigative journalists try to figure out the mystery and understand why the police and FBI had failed. What happened to Alice? "When I Killed You" progresses in two separate timelines. One timeline takes place in the present and focuses on the renewed investigation, while the other is the mother’s memoir. Through the memoir, the reader gains insight into Helen’s life, growing up during the sixties, her relationships, and her foes. Some of the people she encounters end up being suspects, all with solid alibis. Of course, the two timelines eventually merge for a stunning conclusion.