Towards the end of a busy day, Inspector Walter Darriteau returns to his workstation. There was a neatly-written pink notelet on his desk. Please ring Mrs Susan Woodhams, and a local number. He picks up the phone and pokes in the digits. After three rings, a woman answers. 'There's something preying on my mind, ' she says, 'and it has been for more than twenty years.' 'Go on, ' says Walter, imagining it was something and...