The first time she goes out after their daughter is born, Alice leaves the two-week-old infant at home with her husband, David. When she returns two hours later, she insists that the baby in the crib is not her child. Despite her apparent distress, David is adamant that she is wrong.

The police are called to the scene. Detective Constable Simon Waterhouse is sympathetic, but he doubts Alice's story. His superior, Sergeant Charlie Zailer, thinks Alice must be suffering from some sort of delusion brought on by postpartum depression. With an increasingly hostile and menacing David swearing she must either be mad or lying, how can Alice make the police believe her before it's too late?