Centuries after the fall of civilization caused by the rise of predatory machines, a young woman named Aloy, an orphan lovingly raised by an outcast from his tribe, roams the harsh wilderness to discover what caused the catastrophic apocalypse, and seek the answers to her past. Shunned by her own tribe as "motherless", she befriends several members of neighboring tribes and helps them with their tasks using a high tech scanning device she found as a child. A mysterious hacker called Sylens contacts her through the device and gives her hints about where to go next to continue her search for truth. Her quest leads her to the long abandoned headquarters of the private military company that created the machines as perfect weapons some 1000 years before. At some point, the company lost control over the self-replicating machines due to a "glitch", so the company's head and Aloy's lookalike, scientist Elizabet Sobeck, initiated a project called Zero Dawn to make sure that humanity will survive the machine apocalypse. After learning the shocking truth, Aloy and Sylens' ultimate goal becomes discovering the way humanity survived the machine onslaught back in the day in order to stop Helis, a misguided, insane, tribal warlord and sadistic tyrant turned zealot machine cultist, who's under the influence of a "god" called Hades, from taking the control of the machines and eradicating Aloy's as well as all other rival tribes. Later, Aloy reaches a secret underground bunker where holographic records on Zero Dawn are held. The project turns out to be a complex A.I. system called Gaia, a high tech Noah's arc secretly created during humanity's twilight to terraform Earth after the machines eradicate all life including humans and repopulate it again using genetic material stored in its cryostorage through bio-engineering and artificial insemination. In time, the system would also develop the necessary mechanisms to finally disable all rogue robots. Humanity would die out only to be resurrected centuries later. However, a part of Gaia called Hades that was suppose to make sure that this new world was going in the right direction, or destroy it, if it doesn't, and let Gaia try again, began targeting humans once again for no apparent reason. Aloy is then caught by Helis, who reveals his plan to use the robots to kill all other tribes and forces her to fight in a gladiatorial arena against a giant robot beast controlled by Hades. She defeats the robot monster and escapes from Helis and the cultists with the help of Sylens who admits that he once belonged to them himself. Aloy goes to rescue her people from the cultists' wrath and discover a way to either fix or destroy Hades. She eventually learns that one of Elizabet's colleagues went mad and decided to kill the surviving members of her team as well as order Hades to destroy Gaia and make sure that the future humans will never learn of technology that destroyed their predecessors. She also learns from Gaia itself that she is a clone of Elizabet, created to use her DNA to unlock the DNA-coded bunkers that hide the secrets of dormant Gaia and rebuild civilization. Finally, she learns that the only way to stop Hades is to purge its memory from the company's central bunker. Sylens finally comes clean and explains that he was the one who found Hades and helped it take control over Helis tribe in order to learn about the past from it. After parting ways with Sylens, Elizabet unites the tribes against Helis, repels his attack and defeats him. She then takes on the robot guardian of the central bunker and manages to shut Hades down. While the tribes celebrate, she ventures on into the uninhabited wastelands and finds Elizabet's corpse along with an appropriately touching recorded message in which Elizabet tells Gaia what she would have liked the daughter she never had to be like. After the end credits, Sylens is shown capturing the Hades A.I. in order to further uncover its secrets, namely, who was Hades' puppet master that turned it into a weapon of human extinction in the first place.