It seemed to be just another so-called "adventure cruise" among the tropical islands of the Indian Ocean - the adventure being little more than the delivery of mail and stores by Captain Cassidy's coaster, the Sunglow, the loading of mangrove poles and copra, and coping with passengers' complaints about food and ventilation. But this was to be a very different cruise from all the others. Cyclones are almost unheard of in those seas in September, yet it was a cyclone that engulfed and battered the decrepit little coaster and tested passengers and crew to the uttermost. Treasure hunts for missing cargoes of gold inspire scepticism, yet the chart left by Mrs Clutterbutt's great-grandfather seemed uncommonly convincing. Was it one of Sunglow's apparently humdrum passengers who drove the knife into the jugular vein of the mysterious Dada? And the passengers lost overboard in the night. Was it accident, suicide, or something more sinister? What were the so-called geologists doing on deserted Wreck Island?