Robert Blair was about to knock off from a slow day at his law firm when the phone rang. It was Marion Sharpe on the line, a local woman of quiet disposition who lived with her mother at their decrepit country house, The Franchise. It appeared that she was in some serious trouble: Miss Sharpe and her mother were accused of brutally kidnapping a demure young woman named Betty Kane. Miss Kane's claims seemed highly unlikely, even to Inspector Alan Grant of Scotland Yard, until she described her prison -- the attic room with its cracked window, the kitchen, and the old trunks -- which sounded remarkably like The Franchise. Yet Marion