It is June 21st, the longest day of the year, and new mother Camilla's life is about to change forever. After months of maternity leave, she will drop her infant daughter off at daycare for the first time and return to her job as a literary agent. Finally. But after she arrives at the office, police officers storm the foyer: in the city, just near her work, a man has taken three hostages and is now in a tense standoff with law enforcement. And Luke, the person she's loved for more than a decade, the father of her child, is involved. But he is not a hostage. He is the kidnapper. All she has is a half-written cryptic note that Luke left for her. Seven years after the crime that shocked the nation, and her husband's subsequent disappearance, Camilla has slowly accepted that she will never have answers about what really happened that day. But just as she prepares to let Luke go for good, an anonymous location, sent to her by text message, reignites her suspicions about the kidnapping and sends her on a dangerous search for the truth. What follows is a propulsive, twisty story of motherhood, marriage, and the secrets at the heart of our closest relationships.