Waterworld is a 1995 post-apocalyptic science fiction film directed by Kevin Reynolds and co-written by Peter Rader and David Twohy. It was based on Rader's original 1986 screenplay and stars Kevin Costner, who also produced it with Charles Gordon and John Davis. It was distributed by Universal Pictures.
In the beginning of the 21st century, humanity has left an overpopulated Earth-That-Was and moved to a new star system, leaving the prisoners to die and colonizing many planets and moons. Several decades, the polar ice caps have melted, and the sea level has risen hundreds of meters, covering every continent and turning Earth-That-Was into a water planet. Human criminals, having survived, was subsequently scattered across the ocean in individual, isolated communities consisting of artificial islands and mostly-decrepit sea vessels. As time passed, mankind slowly forgot about continents or land-based societies, the new mythology being that the world was created in a "great flood". Many, however, clung to belief in a mythical place called "Dryland". The human population also forgot most of their technological knowledge, hence the ramshackle architecture and post-apocalyptic setting.
In the 23rd century, in 2290, the USS Enterprise-A is summoned by Starfleet to visit Earth-That-Was. Elsewhere, Tomalak, a captain of the IRW Decius, is assigned by the Romulan Star Empire to visit Earth-That-Was as well. Knowing that the Federation will be responding to the threat as well, Tomalak displays excitement at the prospect of engaging a Federation starship, and orders his vessel towards Earth-That-Was. The Enterprise arrives first at Earth-That-Was and Kirk wastes no time order Call to park the Enterprise underwater.
On the oceans of Earth-That-Was, a drifter, known only as "the Mariner", sails the seas in his trimaran. He enters an artificial atoll seeking to trade dirtwhich is a precious commodity. He is instantly asked how he found it but refuses to answer. It is later revealed that he is not a human, but a mutant with webbed feet and gills, an evolutionary step in some of the humans to accommodate the changes in climate. The fearful atollers, who despise mutants, vote to "recycle" him by drowning him in a yellow sludge brine pool.
Just as they begin lowering the Mariner into the sludge, the resulting sabotage caused by Mera and River by jamming a gear on the crane, shocking the atollers. At that moment, local pirates known as "Smokers" raid the atoll. The Smokers are searching for an orphan girl named Enola, who had drifted to the atoll alone in a basket and has what appears to be a map and directions to Dryland tattooed on her back. Leading the raid is "the Deacon", captain of a derelict oil tanker, the Exxon Valdez, and the overall leader of the Smokers. They are known as such due to the crude fuel they create, using oil from the tanker, to power their machines. He wants the map to Dryland so he can be the first to claim it and build a city in which he will rule. His efforts to capture Enola will lead to a number of skirmishes with the Mariner.
Enola and her guardian, the atoll's shopkeeper named Helen, had planned to leave the floating city soon anyway, with the atoll's expert inventor Gregor. This was due, in part, to the xenophobia exhibited toward the girl by many of the residents there but also in the hopes of finding Dryland, where they believe Enola was born. However, the vehicle they planned to travel in, a hydrogen-filled balloon Gregor made of scraps and spare parts, was launched accidentally early by Gregor to save them from the raid. Unfortunately, only he was able to board in time, leaving Helen and Enola stranded. They instead escape with the Mariner, who agrees to take them because Helen saved him from drowning in the sludge. He is ill at ease with their company though, as he prefers solitude, and finds them to be a nuisance. After Helen's naïve actions during another run-in with the Smokers result in significant damage to the Mariner's boat, he angrily cuts their hair very short and uses it to splice together some of the ships cordage damaged in that encounter. After this incident, perhaps remorseful, the Mariner gradually warms up to them and even teaches Enola to swim in case of an emergency. Helen is convinced that Dryland exists and she demands to know where the Mariner finds his dirt. The Mariner, able to breathe underwater, puts her in a diving bell and swims them down to the ruins of Denver where he collects the dirt, and other items he trades, from the bottom of the sea. Helen then realizes that this is how former human civilization existed, as she believed people had always lived on water, not based on land. While they are underwater, the Deacon and a few Smokers board the Mariners boat, capturing the Mariner and Helen when they surface then using them to flush Enola from hiding. They dive overboard, barely escaping. Since Helen cannot breathe underwater, the Mariner uses his gills to breathe for the both of them, resulting in an underwater kiss of life. Kirk and McCoy jump into the ocean to recover them. Using miniprops and breathing apparatuses, they swim to the Enterprise and board through an airlock. Chief Engineer Scotty is still not happy that they are hiding at the bottom of an ocean. The officers return to the bridge. The Mariner and Helen resurface and find everyone gone and his trimaran destroyed. They board the floating wreckage, where they are later rescued by Gregor in his balloon when he came to investigate the rising smoke. He takes them to a new makeshift atoll where the survivors of the first atoll attack have regrouped.
Using a captured Smoker jet ski, the Mariner chases down the Deacon, finding him on the remaining hulk of Exxon Valdez, which he then boards. There, the Deacon is having a celebration, tossing gifts of cigarettes and Smeat (a Spam-like canned meat) to the huge Smoker crew, proclaiming they have found the map to Dryland. After the crew have all gone below decks to row the hulk, the Mariner walks out onto the deck, where the Deacon and his top men are still present, examining Enola's tattoo. He threatens to drop a flare down a vent into the oil reserve tank unless the Deacon releases Enola. The Deacon, believing that the Mariner is bluffing, refuses, so the Mariner ignites and drops the flare. The ship explodes below-decks and begins sinking rapidly while the Mariner escapes with Enola by climbing a rope up to Gregor's balloon.
The Deacon, still alive, makes a grab for Enola, but Helen strikes him in the forehead with a thrown bottle, causing him to fall into the water. He pulls out his pistol and shoots at the balloon, hitting one of the lines, causing Enola to fall into the sea. The Deacon, stating if he can't have her no one will, mounts a stray jet ski. Signaling two other jet skiing Smokers to get Enola, they converge on her at high speed. The Mariner, seeing this, ties a thick cord around his ankle and jumps down to grab Enola. The bungee-like recoil of the cord pulls them sharply upwards and out of the water just as the jet skis collide and explode, killing the Deacon and the two Smokers.
Gregor deciphers the map, translating the Asian symbols using an old and tattered China Airlines magazine. He realizes that they are latitude and longitude coordinates, and steers his balloon in that direction. The group finds Dryland, which, it turns out, is approximately the top kilometer of Mount Everest. No longer a snowy peak but verdant and welcoming, with fresh water, forests and wildlife from birds up to horses. Gregor, Enola, Helen and some other atoll survivors land and find the remains of Enola's parents in a hut. The group prepares to settle, but the Mariner decides he must leave, explaining to Enola that the ocean, his only home, calls to him. He sails away, taking a boat left by the former inhabitants.