'He had just learnt to walk,' she said. 'He was playing on a blanket on the floor and then suddenly he was gone.' She tried to dry her tears. She was only nineteen years old, though she somehow seemed younger. 'I know that it's my fault. You can tell me, I know what you're thinking. I should have kept an eye on him, but I was only away for a few minutes.' A 16-month-old boy with Down's Syndrome is found naked and drowned in a pond right by his home. Chief Inspector Konrad Sejer is called to the scene as there is something troubling about the mother's story. As even her own family turns against her, Sejer is determined to get to the truth.