Ida Joner gets on her brand-new bike and sets off toward town. A good-natured, happy girl, she is looking forward to her tenth birthday. Thirty-five minutes after Ida should have come home, her mother starts to worry. She phones store owners, Ida's friends, anyone who could have seen her. But no one has.

Suspicion immediately falls on Emil Mork, a local character who lives alone and hasn't spoken since childhood. His mother insists on cleaning his house weekly—although she's sometimes afraid of what she might find there. A mother's worst nightmare in either case: to lose a child or to think a child capable of murder. As Ida's relatives reach the breaking point and the media frenzy surrounding the case begins, Inspector Konrad Sejer is his usual calm and reassuring self. But he's puzzled. And disturbed. This is the strangest case he's seen in years.