Waterworld

In 2500, sea level rises have put every continent on Earth underwater. The remains of human civilization live on makeshift floating communities built out of scavenged materials known as atolls , having long forgotten about living on land. Rumors of a "Dryland" still exist, but it is considered a myth by most. The Mariner, a lone drifter, arrives at an atoll on his trimaran to trade dirt , a rare commodity, for supplies.

When the locals see that the Mariner is a mutant, with gills and webbed feet, several accost him and he kills one in self-defense. As a result, the Mariner is sentenced to be drowned in a tank of organic sludge. While the Mariner is trapped in the tank, the atoll is attacked by the Smokers, a formidable pirate gang that has been systematically raiding and destroying atolls. Helen, a strong-willed atoll resident, tries to escape on a gas balloon dirigible with her young ward Enola and inventor Gregor.

However, Gregor accidentally departs with only himself on board, stranding the two. She frees the Mariner on the condition he takes them with him. The Mariner skillfully fights his way out, damaging the Smokers' forces and causing an explosion that blinds its leader, Deacon, in one eye. The Mariner, Helen and Enola board the trimaran and escape.

Following a brief skirmish with the Smoker's scout seaplane , the trio encounters a drifter suffering from cabin fever whom the Mariner kills after a trade gone awry, and a mutated shark the Mariner kills for food. Despite his initial reluctance and gruff attitude, the Mariner slowly warms up to his companions and has a bonding moment with Enola teaching her to swim. After evading a trap set by the Smokers, the Mariner confronts Helen about their unusual persistence. She admits they are after Enola, for the supposed directions to Dryland tattooed on her back and demands to know where the Mariner collected his dirt.

He takes her in a jury-rigged diving bell and shows her the underwater remains of Denver, Colorado and the soil on the ocean's floor, crushing her belief in Dryland. When they surface, the pair find that the Smokers have caught up. They capture Enola and try to kill Helen and the Mariner before the two dive underwater. The Smokers set the trimaran on fire and leave.

Sorting through the wreckage of his boat, the Mariner sees a collection of National Geographic magazines and compares their images to Enola's doodles, realizing she was drawing Dryland objects. Gregor, having spotted the smoke from his dirigible, finds Helen and the Mariner and takes them to a new makeshift atoll. The Mariner takes a captured Smoker's jet ski to chase down the Smokers' base of operations, the remains of the Exxon Valdez , where they manage to manufacture fuel, ammunition and cigarettes. Deacon's advisors struggle to decipher the tattoo.

To keep his followers' minds off their dwindling resources, he bluffs that he has decoded the map on Enola's back and orders them back to their stations to row. The Mariner infiltrates the "'Dez" and confronts the Deacon, threatening to ignite the oil reserves in the hold unless Enola is returned. The Deacon calls the Mariner's bluff, knowing that it would destroy the ship, but to his shock, the Mariner drops a flare into the oil reservoir. The ship is engulfed in flames, and begins to sink.

The Mariner rescues Enola, escaping via a rope from Gregor's balloon with Helen and the Atoll Enforcer aboard. The Deacon fires on the balloon, shaking Enola into the ocean. As the Deacon and some of his men converge on her, the Mariner makes an impromptu bungee jump from the balloon to grab Enola before the Deacon and his men collide on their jet-skis, inducing an explosion that kills the three. Gregor later identifies Enola's tattoo as coordinates with reversed directions.

Following the map, the balloon party discover Dryland, covered with vegetation and wildlife. They also find a hut with the remains of Enola's parents. The Mariner, feeling that he does not belong on Dryland, takes an old wooden catamaran from the island and departs, as Helen and Enola bid him farewell. Ulysses Cut The extended edition, dubbed the "Ulysses Cut", has a runtime of 171 minutes and features scenes fleshing out the characters and settings.

It identifies the Dryland as Mount Everest , and ends with Helen giving the Mariner the name Ulysses .