A young thirtysomething couple goes on holiday to the Caribbean. One of the fun activities open to them is scuba diving off a reef several miles out. Due to a faulty head count taken by the dive boat crew, the couple is left behind in the open ocean. They find themselves drifting endlessly for hours on end, facing dehydration, saltwater sickness, jellyfish stings, and the most frightening menace - sharks! Although several boats and ships pass by within the couple's view, none sees them, and they are not discovered missing until the following morning when the dive boat crew discovers their gear on the boat, and their hotel manager discovers they never returned to their room. Frantically a search is mounted by plane, boat and helicopter. But it may be too late for the young couple, adrift in the....Open Water! Based on a true story from the South Pacific.