Excerpt: 'In April, 1873, Henry Vane was sitting on the perron of a small summer house in Brittany, poking the pebbles in the driveway with his cane. He had been there for half an hour, and there was nothing in his appearance and attitude to indicate that he would not be there for half an hour more. There was one red pebble, in particular, which he had an especial desire to prod out from among the...