Near a huge waterfall, a humanoid alien watches a starship leave the planet before retrieving a pot
with a black liquid that it proceeds to drink. Immediately the liquid begins taking over its
body, making its skin black and dissolving its DNA, causing the alien to fall into the water.
Its body begins dissolving as well, leaving its DNA to be taken away by the current. In 2089, a
team of archeologists led by doctors Elizabeth and Charlie find some paintings in a cave in Scotland
that are at least thirty-five thousand years old. They match a series of paintings they've found all
over the world from cultures that couldn't have shared the same information. Two years later,
the starship Prometheus leaves Earth. The whole crew is under cryosleep, and the one in charge
of taking care of things is David, a robot. He uses his free time to get to learn more about
being human, like playing sports, watching movies, dying his hair, and learning ancient languages.
He also likes to spy on the crew's dreams. For example, Elizabeth dreams of the time she was
a little girl and watched an African tribe bury one of their men, her father had to explain to
her how each culture had different beliefs when it came to death. After two years of traveling,
the ship reaches its destination, and David wakes up the whole crew consisting of mercenaries and
scientists. Everyone gets time to recover from the side effects and to get some food on their empty
stomachs, although Captain Janek also puts up a Christmas tree because they missed the holidays.
This is seen as dumb by Meredith, the person in charge of overseeing everyone's doing their jobs
right. Soon the mission brief begins, and Meredith plays a holographic recording of Peter, the CEO of
Weyland Corporation, which is the company funding this expedition. He explains that by the time they
watch this he's already dead, and that David's the closest thing to a son he'll never have. Peter
has always wanted to know where we come from and what happens when we die, which is why he funded
this expedition when Elizabeth and Charlie came with him with a theory. The doctors take over the
floor and explain the paintings they found all over the world depicted a star map that could
take them to a planet with its own sun that could sustain life, and that's where they are now. They
think this map was left by some aliens Elizabeth calls "Engineers" because her theory says they
were the ones that created humankind, although the rest of the crew is skeptical. Moments later,
Meredith calls the doctors to come to her private quarters, where she has her own medical pod and
self-contained life support. Meredith explains that she doesn't believe those cave scribbles
meant anything and she's doing this for Peter, thus it's her responsibility to be sure the
money isn't wasted. If the doctors make find life, they're forbidden from making contact, which makes
the doctors wonder why they even came then. David spent the last two years deconstructing dozens of
ancient languages and is sure he can communicate with the Engineers, but when he sends a message
to the planet, nobody responds. The crew decides it's time to land and the ship goes through the
atmosphere, detecting no radio signals or heat sources, which should mean there's no civilization
down there. However Charlie notices some straight lines on the ground that couldn't have happened
naturally, and the ship lands on that spot. The crew gets ready to go on the expedition and David
wears a suit even if he doesn't need it because he was designed to blend in among humans. The group
takes a series of vehicles to visit a dome-like structure that geologist Fifield can't tell if
it's natural or not, but he's sure it's hollow. Once they get inside, Fifield sends two special
probes that map the whole area, allowing them to find their way through a series of corridors. When
they go deeper, they find a source of water that is heated by the sunlight, and the CO2 levels are
acceptable. While outside it's completely toxic, it seems inside here it's breathable. Charlie
assumes these aliens had been terraforming and takes the risk of removing his helmet,
confirming it's completely fine. Then everyone removes their helmets to keep exploring, and
David finds a wall with a weird goo and various symbols on it, which he activates thanks to his
language knowledge. This causes a sudden hologram of running figures to appear through the corridos,
and the crew follows them until they find the body of an alien lying next to the door that killed it.
Fifield can tell things are getting dangerous and a geologist won't be needed, so he and biologist
Millburn decide to go back to the ship. While the doctors inspect the body, David manages
to open the door, and they find the alien's head on the other side in a great conservation state.
The rest of the crew finds more bodies, indicating the species is extinct. This room has worms in it,
showing life is possible here, but also a monolithic statue of a humanoid head, murals
on the ceiling, and a bunch of stone cylinders. David notices the cylinders are sweating and soon
one of them begins to expel a black organic substance. Elizabeth doesn't notice because
she's looking at the murals, which have started to change. She thinks they've affected the atmosphere
in the room and they need to leave, so she and Charlie begin to bag the head to take away while
David steals one of the cylinders as he comes to the conclusion that the cave is a tomb. At
that moment, Janek discovers there's a dangerous storm incoming and calls the doctors to warn them,
Meredith gives them fifteen minutes to make it back before she closes the ramp. The crew runs out
of the cave and drives as fast as possible, making it back to the ship just in time. However the
alien head falls from the vehicle in the process and Elizabeth goes back to grab it, causing the
storm to hit her and enter the ship. Charlie tries to rescue her by driving the vehicle through the
wind but he ends up getting stuck as well, and in the end they must be pulled away by David with a
set of wires. Afterward the crew begins working on decontaminating their bodies and the hangar,
only to discover Millburn and Fifield haven't come back yet. It turns out the two scientists are lost
inside the cave. Janek manages to contact them to explain they can't pick them up because of the
storm, meaning they'll need to wait until morning. Meanwhile the team sterilizes the head and a quick
scan reveals it's not an exoskeleton, it's a helmet. When they open it, they find a humanoid
alien head inside with new cells changing on its forehead, so they decide to run a stem line into
his brain to make it think it's alive. The trick works and the face starts gesturing, but things
go wrong quickly and the overstimulation ends up making it explode. Elizabeth takes a closer
look at the sample she took from the head and is delighted to discover that its DNA matches
a person's, meaning her theory had been right and these guys created the human race. Meanwhile David
goes to offer an update to a cryosleep pod that holds a mysterious person. Nobody else
knows about it except for Meredith, who violently demands David tell her what the person said. David
only says they were asked to "try harder". Then David goes to inspect the cylinder he brought in
private, and inside he finds a bunch of capsules with a black liquid inside. This gives him an
idea, and he decides to visit Charlie to share a drink with him as they wonder how far they'd go to
get the answers they want. Afterward, Charlie joins Elizabeth in her room and she gets to
share the news about the DNA, so they celebrate by getting frisky. In the cave, Millburn and Fifield
are looking at a creepy pile of alien bodies when they suddenly get a call from Janek, who warns
them that the scanner found signs of a life form nearby. The scientists begin to worry, but just
like that the ping on the scanner disappears, and Janek blames it on a glitch. Eventually
Millburn and Fifield come across the room with the monolith and find the black liquid coming
out from the cylinders. To their surprise, they find a reptile-type alien swimming in the liquid,
and when Millburn comes closer, the creature gets attached to his arm to try to break it. Fifield
cuts the creature off to help him only to get the alien's corrosive fluid sprayed on his helmet,
which eats through the plastic and reaches his face. While Fifield agonizes in pain, the creature
gets inside Millburn's suit and kills him. The next morning, Charlie wakes up feeling unwell and
notices there's something weird in his eyes. Janek calls everyone to inform them the storm's gone but
he can't make contact with the scientists, so they'll go looking for them. His men couldn't
find the glitch on the scan either, thus David promises he'll find the probe and fix it. However
while the group searches the cave, David stays behind on purpose and takes his own path, sending
a recording of what he sees to Meredith. He finds another room full of thousands of cylinders and
alien armor, then takes a corridor to a chamber with a bunch of cryosleep capsules. David cuts
Meredith off before activating a machine in the center of the room that shows him holograms of
the Engineers looking at a star map that includes Earth. When the show is over, David notices one of
the cryosleep capsules is glowing because it still has a live Engineer inside. Meanwhile Charlie
keeps tripping during their search and Elizabeth notices he's sick, but he keeps going anyway.
When they finally find Millburn's body, they come closer to inspect it and cause the little reptile
alien to jump out and slither away. Yet Fifield is nowhere to be seen. At that moment, Charlie starts
to feel really sick, so Elizabeth asks everyone to go back in order to quarantine Charlie. By the
time they return to the ship, Charlie's skin is starting to turn black, and Meredith meets
them at the hangar with a flamethrower in hand because she doesn't want Charlie aboard. Janek
and Elizabeth start arguing with her, but Charlie thinks he has no future and walks to Meredith
on purpose to make her toast him to the ground while Elizabeth watches in agony. Moments later,
the crew is quarantined and David runs tests on Elizabeth to check Charlie didn't infect her. To
their surprise, the scan shows her to be three months pregnant, which is impossible because
three months ago she had been under cryosleep. The fetus has a creepy weird shape as well and
Elizabeth wants it out, but David points out they don't have the means or personnel to perform
such surgery. Suddenly Elizabeth's abdomen beings hurting terribly, so David gives her some medicine
to make her sleep. Some minutes later, a few crew members wake Elizabeth up in order to take her to
a cryosleep capsule until they can decide what to do with her fetus. Elizabeth refuses to keep
this thing and fights everyone off before running away until she finds Meredith's medical pod. She
asks for a caesarean, but for some reason the pod is only calibrated for men and can't do it,
so instead Elizabeth asks for the extraction of a foreign body. The machine accepts this and gives
her some anesthetics, but they aren't strong enough and she still feels unbearable pain as a
claw removes the strange fetus from her body. The fetus immediately pops and a creepy alien comes
out of it, which begins shaking its tentacles to try to free itself. Elizabeth has to stand the
attack while the machine closes her wound, but as soon as the stitches are done, she leaves the pod
and locks the alien inside it, leaving it to be put to sleep by the anesthetics. In the meantime,
Janek notices something weird standing in front of the ship and one of the crew members goes to
check. It turns out to be a mutated Fifield, who begins attacking all the people in the hangar. A
fierce fight begins among all the men, and since bullets don't do anything to Fifield, they end
up using the flamethrower to kill him. Elizabeth wanders around the ship until she makes it to the
infirmary to ask for medicine, and there she's surprised to discover Peter is still alive - he
was the guy in the extra cryosleep David had been talking to and the medical pod had been for him.
Peter wants to meet his maker directly and demand answers, so David will take him to the Engineer he
found in the cave. Elizabeth tries to explain this planet is dangerous and not what they thought,
but her warnings are ignored. Unwilling to give up, Elizabeth pushes through her pain and suits
up to go back into the cave. Janek finds her and points out this can't be the Engineer's
home planet, the cave is probably some military installation where they were making that black
liquid as a weapon of mass destruction that leaked and killed them. Janek wants to return to Earth,
but Elizabeth convinces him to wait until she gets in contact with the remaining living Engineer.
Peter is getting ready to leave too and Meredith comes to try to stop him from dying in some hole
as she calls him "father", but Peter ignores her warnings as well. When the crew reaches the cave,
David tells everyone to take off their helmets because he knows the disease isn't in the air,
implying he was the one that put the black liquid in Charlie's drink. The crew reaches the new room
with the thousands of cylinders and David calls it a "cargo hold", this new scan angle makes
Janek and Meredith realize this isn't a cave, it's a starship. David activates the machine
while he explains the Engineers were in the process of leaving for Earth when they lost
control of the black liquid that killed them. The last Engineer is woken up, and Elizabeth
tries to ask some questions, but Peter makes one of his mercenaries shut her up with a hit before
he begins asking philosophical questions of his own. David translates into Proto-Indo-European,
but the Engineer reacts by taking David's head and using it to kill Peter. Then he pushes Elizabeth
away to kill the mercenaries that are wasting bullets on him. Back on the ship, Meredith sees
Peter's death through David's eyes and orders Janek to get things ready to leave the planet.
Elizabeth runs away as the Engineer activates its own ship to fly to Earth as well. This opens lots
of areas on the ground and Elizabeth jumps through them as she calls Janek to tell him to stop the
Engineer or the black liquid will make it to Earth and destroy humanity. Prometheus isn't
a battleship and Meredith thinks they should leave without doing anything, but Janek ignores
her and orders his pilots to warm up the ion propulsion, which will transform the ship into a
bullet. Meredith runs out of the ship, and Janek gives permission to his pilots to do the same,
but the pilots respect their captain and would rather go down with him. In mere seconds,
both ships are crashing in the air, successfully stopping the Engineer from leaving. However the
ships now fall to the ground, and Elizabeth and Meredith have to run away before they get crushed.
Meredith isn't fast enough and dies, but Elizabeth manages to survive by finding cover next to a
rock. Then Elizabeth goes into Prometheus to get some supplies and hears some noises deeper inside.
After grabbing an ax to defend herself, she goes to investigate and discovers her alien offspring
has escaped the medical pod and has grown into a huge size. At that moment, David contacts
Elizabeth and tells her to run, but it's too late: the Engineer shows up and pushes Elizabeth against
the wall to kill her. Elizabeth thinks fast and opens the door behind her, which releases the
alien offspring that immediately jumps on the Engineer. As Elizabeth runs away, her offspring
thrusts an ovipositor down the Engineer's throat and subdues him. Outside the ship, Elizabeth's
having a breakdown when he's suddenly contacted by David, who explains the Engineers have more
ships underground and he can pilot them. Elizabeth goes to rescue both David's head and body, but she
has a request: instead of returning to Earth, she wants to go to the Engineers' home planet,
and David accepts even if he doesn't understand why she's so desperate for answers. Before David
and Elizabeth leave the planet on an alien ship, Elizabeth returns to Prometheus one last time to
send a message to Earth explaining what happened. Moments later, from inside the dead Engineer,
a black alien emerges, confirming this story is the predecessor to Ripley's tale.