As a spacecraft departs a planet, a humanoid alien drinks a liquid, causing its body to dissolve. Its remains cascade into a waterfall and the alien's DNA falls apart and recombines.
In 2089, archaeologists Elizabeth Shaw and Charlie Holloway discover a star map in Scotland that matches others from several unconnected ancient cultures. They interpret this as an invitation from humanity's forerunners, the "Engineers". Peter Weyland, the elderly CEO of Weyland Corporation, funds an expedition, aboard the scientific vessel Prometheus, to follow the map to the distant moon LV-223. The ship's crew travels in suspended animation while the android David monitors their voyage. They arrive in December 2093.
The Prometheus lands on the barren, mountainous surface near a large, artificial structure, which the team explores. Inside, they find stone cylinders, a monolithic statue of a humanoid head, and the decapitated corpse of a large alien, thought to be an Engineer; Shaw recovers its head. The crew finds other bodies, leading them to surmise that the species is extinct. Crew members Millburn and Fifield grow uncomfortable with the discoveries and attempt to return to Prometheus, but get lost in the structure. The expedition is cut short when a storm forces the crew to return to the ship. David secretly takes a cylinder with him, while the remaining ones begin leaking a dark liquid. In the ship's lab, the Engineer's DNA is found to match that of humans. David investigates the cylinder and the liquid inside. He intentionally taints a drink with the liquid and gives it to the unsuspecting Holloway, who had stated he would do anything for answers. Shortly after, Shaw and Holloway have sex.
Inside the structure, a snake-like creature kills Millburn and sprays a corrosive fluid that melts Fifield's helmet. Fifield falls face first into a puddle of dark liquid. When the crew returns, they find Millburn's corpse. David separately discovers a control room containing a surviving Engineer in stasis and a holographic star map highlighting Earth. Meanwhile, Holloway sickens rapidly. He is rushed back to Prometheus, but mission director Meredith Vickers refuses to let him aboard. At his urging, she burns him to death with a flamethrower. Later, a medical scan reveals that Shaw, despite being previously infertile, is now in advanced pregnancy. Fearing the worst, she uses an automated surgery table to extract a squid-like creature from her abdomen. Shaw then discovers that Weyland has been in stasis aboard Prometheus. He explains that he wants to ask the Engineers how not to die from old age. Vickers addresses him as "Father".
A monstrous, mutated Fifield returns to the Prometheus and kills several people before being killed. The captain of Prometheus, Janek, speculates that the structure was an Engineer military base that lost control of a virulent biological weapon, the dark liquid. The structure also houses a spacecraft. Weyland and the team return to the structure, accompanied by Shaw. David wakes the Engineer from stasis and speaks to him in Proto-Indo-European[4] to try to explain what Weyland wants. The Engineer responds by decapitating David and killing Weyland and his team, before reactivating the spacecraft. Shaw flees and warns Janek that the Engineer is planning to release the liquid on Earth, convincing him to stop the spacecraft. Janek and the remaining crew sacrifice themselves by ramming the Prometheus into the alien craft, ejecting the lifeboat in the process. The Engineer's disabled spacecraft crashes onto the ground, causing the death of Vickers. Shaw goes to the lifeboat and finds her alien offspring is alive and has grown to gigantic size. The Engineer forces open the lifeboat's airlock and attacks Shaw, who releases her alien offspring onto him. It thrusts an ovipositor down the Engineer's throat, subduing him. Shaw recovers David's remains and, with his help, launches another Engineer spacecraft. She intends to reach the Engineers' homeworld in an attempt to understand why they wanted to destroy humanity. In the lifeboat left on the planet, an alien creature bursts out of the Engineer's chest.
