The Charnocks, a wealthy landowner family from Virginia, take their yacht on a cruise to the South Pacific. The yacht catches fire near a desert island, and while John Sr. dies in the fire, his wife and son make it to the island, where she soon dies. Twenty years later Katherine Brenton, a wealthy young woman, is on a yacht trip in the South Pacific with playboy Valentine Langford, testing her theory that men and women can have platonic relationships under any conditions. When Langford makes a pass at her she knocks him out and flees the yacht for a nearby desert island--which happens to be the same one that young John Charnock was stranded on 20 years earlier. They soon find each other. Complications--and an earthquake--ensue.