In the future. When the polar ice caps melt, the Earth becomes engulfed by water. Drifters sail across the waters of the world on their man-made ships, trading for supplies and salvaging what is left of civilization. Communities of survivors lives in towns called 'Atolls.' Evil pirates known as 'The Smokers' travel across Waterworld in search of a mythical island called 'Dryland.' The Mariner is a mysterious drifter who arrives at an Atoll. He is sentenced to death when the community discover he is a mutant. Led by their evil leader, Deacon, The Smokers attack an Atoll. A woman named Helen and her adopted daughter Enola bribes The Mariner to take them to Dryland. The Mariner, Helen and Enola are pursued by Deacon and the Smokers, when The Mariner learns the tattoo on Enola's back is in reality a map that will lead them to Dryland.