Widely considered to be an expensive failure, Waterworld was an epic vehicle for Kevin Costner, who starred in and co-produced the film, with his friend Kevin Reynolds as director. It was based on a 1986 screenplay by Peter Rader and cost an estimated $235 million, more than any film in history up to that time.
Costner eventually fired Reynolds and directed the last few scenes himself. The story was filmed in Hawaii, using several artificial islands, and is set in an apocalyptic future, after global warming has melted the polar ice caps and flooded civilization. The Mariner (Costner) is one of the human beings who has adapted by growing gills.
The survivalist lives on a boat on which he is growing a precious tomato plant. He tries to sell the plant and its dirt to the residents of an artificial island built of industrial waste. They imprison him when they discover that he's a mutant with gills.
But the island is attacked by the Smokers, a group of oil-guzzling raiders on jet skis headed by the Deacon (Dennis Hopper). The Mariner escapes with Helen (Jeanne Tripplehorn) and her daughter Enola (Tina Majorino). Back at sea, the Smokers repeatedly attack, using planes and boats, until they kidnap Enola.
Enola's back is tattooed with a map showing how to get to Dryland, the last unflooded area on Earth. But Deacon, who needs to get to Dryland to replenish the Smokers' oil supply, can't immediately decipher it.