A U.S. Naval aircraft on a routine weather patrol in the Caribbean encounters 'Mabel', a ferocious hurricane that should, nevertheless, pass harmlessly among the islands. But David Wyatt, civilian weather expert, has developed a sixth sense about hurricanes and is convinced that Mabel will change course and strike the island of San Fernandez and its capital, St Pierre. Scientific evidence is against him, the Commander of the U.S. Base refuses to evacuate, and Wyatt's lone voice is finally overwhelmed when a rebellion against the tyrannical dictator who rules San Fernandez sweeps down on St Pierre. Wyatt is forced to pit himself against insuperable odds, aided only by a small and diverse group of English and American civilians - and by Hurricane Mabel herself.