The Mariner is a mutant trader, adrift in a dystopian future where Earth is submerged under water and humankind struggles to survive on boats and in ramshackle floating cities. The Mariner becomes embroiled with the Smokers, a gang of pirates who, led by villainous leader Deacon, are seeking Enola, a girl with a map to the mythical realm of Dryland tattooed on her back.