The film is set in a large and dystopian city, where the night never ends. People have vague memories of other locations, but nobody seems to be ever exiting the city. John Murdoch awakes in the bathtub of a hotel room, and realizes that he does not remember his own name or where he is. Within hours, he learns that he is a suspected serial killer (despite having no taste for killing or harming people), that he has an estranged wife who loves him (despite not recalling any meetings with her), that he has an elderly uncle who raised him like a son (and who he has trouble remembering), and that he has a strange fondness for fish (who he has an urge to protect). John is on the run from the Strangers, a dying race of telepaths and telekinetics who secretly control this city. He has somehow developed a copy of their own superpowers, and he is seen as an existential threat to them. While seeking the truth about his identity, John learns that the humans of this city have been implanted with false memories. And that the city itself transforms every few hours. His only real source for information is a mad scientist who has his own agenda.