Naomi seems to have everything. A beautiful daughter, a gorgeous house, a perfect life. Behind the scenes, though, she and her husband are drifting from one another and struggling to conceive their second child. Then Naomi meets a parent at her daughter's nursery. Sean understands her, or so she thinks. Looking for a connection, for a friend, she joins him at a swimming lesson with their children. That day, Naomi makes a terrible mistake. Weeks later, when Naomi attempts to contact Sean, he has disappeared without a trace. But as she begins to piece her life back together, it becomes clear that someone else knows her secret. Someone who wants to make sure she never forgets what she did at the pool. An intelligent, searing and addictive thriller about family, desire and the lengths people will go to for the ones they love the most.