Kevin Costner stars in this sci-fi adventure set on a future Earth which is submerged in water. Humans have to survive on makeshift floating cities, although some of them are determined to find a place known as Dryland. Only the young Enola (Tina Majorino) knows the secrets of this mythical place and she becomes a pawn in the power struggle between the Mariner (Kevin Costner) and his evil nemesis Deacon (Dennis Hopper).