Primordium is a 2016 American science-fiction horror film written and directed by Matt Reeves and starring Tom Cruise, Brie Larson, Oscar Isaac, Alice Braga, Omar Sy, Sharlto Copley, Claudia Kim and Christoph Waltz. It follows the lives of a research team on the Primordium space station, that when shelters an experiment chimpanzee running from attackers, have their crew killed one by one, with a creature that is both a parasite and a mimic.
In the year 2089, on Mars, a Russian group of researches pursue a escaping Chimpanzee on a exploratory car to an American research and reconnaissance station. On their way, a Russian accidentally drops a grenade, destroying the car and killing himself in the process. The surviving Russian continue to pursue the chimp, eventually firing with a assault rifle until he shoots Chester Briggs (Sharlto Copley) on the leg. This act prompts the station commander, Ken Gilligan (Tom Cruise) to shoot the Russian dead. Not knowing what to do about the incident, Johann Adler (Christoph Waltz) allows the chimpanzee to enter and the crew to adopt him.
Unable to contact NASA, the station's computer, Athena, ends up detecting a mysterious transmission coming from the Russian outpost, and reveals it to Diana Williams (Brie Larson), who assumes it could be members of the Russian station whom were attacked by the two rampant explorers. Required by standing orders from their corporate employers to investigate the signal, Ken and Marco Santiago (Oscar Isaac) go investigate, hoping to find answers and possibly victims. There they find the whole base destroyed, most of its personnel missing, and one member dead of apparent suicide, whose ribs appear to have been exploded outward from the inside. Finding evidence that the Russians had dug something out of a distant crater, Marco explores more, only to find a dismantled research room containing a mysterious device and numerous eggs, one of which releases a creature that attaches itself to his face.
Ken return to the station with the unconscious Marco and the partially-burned remains of a hideous creature composed of station members Erik and Ivan which bears some human features, where Johann demands to allow both to enter, defying Diana's orders to follow the station's quarantine protocol. On the station's laboratory, Doctor Cheol Han (Claudia Kim) unsuccessfully attempted to remove the creature from Kane's face, discovering that its blood is an extremely corrosive molecular acid, finding that the creature had what appeared to be a normal set of human internal organs.
At that night, at Briggs' request, Jackques Du Lac (Omar Sy), the station's animal handler, kennels the chimpanzee alongside other research apes. However, noises from the kennel cause Jacques to return, finding almost all monkeys being assimilated by the chimpanzee, which has transformed into a creature. Ken notices the commition and fire the station's alarm, with every crew member gathering into the kennel. Ken and Chester shoot the creature to no harm, but it is eventually killed when Ana Ramos (Alice Braga) appears and incinerates it with a flamethrower. A subsequent autopsy by Cheol reveals that the chimpanzee was an parasitic creature capable of absorbing and perfectly imitating other life-forms. Realizing the implications of this, Cheol quickly becomes withdrawn and suspicious of the others. A second car expedition near the Olympus Mons discovers an alien spacecraft unearthed by the Russian research team, revealing that the creature had awakened from a destroyed spaceship after being buried within the ice for thousands of years.
The other day, Marco awakens and seems healthy, with the creature that was attached to his face dead. During the crew's meal, however, Marco chokes and convulses in pain before a small creature, similar from the one found emerging from the dog, bursts from his chest, killing him, and escapes into the depths of the ship. The crew attempt to locate and capture the creature by fashioning motion detectors. Ana and Johann quarantine the storage room, while Diana confers to Ken in the station's car that Cheol is becoming unstable and her research indicates the burned creatures are still alive. Moments after Johann left, strands of tentacles from the creature who emerged from Marco appears, and proceeded to assimilate Ana. Johann returns to find the creature assimilating Ana; the team corners the alien in mid-transformation and burn it with fuel.
Cheol, meanwhile, has calculated that if the creature manage to escape Mars with one of the station's ships, it will assimilate the entire planet within three years upon reaching civilization and suffers a mental breakdown: to prevent the alien from escaping, she disables the helicopters, tractors, kills the remaining apes, and proceeds to wreck the radio room until the team overpowers her and lock her in the tool shed. Now isolated, the crew realizes that they might be contaminated and speculate on how to determine who is human. Chester finds that the medical blood supply has been destroyed, seemingly by the creature, eliminating the chance of blood tests that could reveal the infected party; because the perpetrator used Ken's keys to access the blood, the team nearly dissolves into rampant paranoia as to who is guilty. Ken puts Jacques into isolation, fearing he could be infected duo to contact with the chimpanzee, and orders Hank Zavimbe (Chiwetel Elijiofor) to continue Cheol's work before an encroaching sand storm forces them inside tight quarters.
Seeking to kill the creature set loose, Ken enters the shafts intending to force the alien into an airlock where it can be ejected into the unbreathable surface of Mars, but the creature, now already mimicking someone else, ambushes and kill him. Jacques implores the remaining crew members to escape in the base's ship, but Diana, now in command, explains that the shuttle will not support all of them. At night, Hank, attempting to continue Cheol's research, goes missing shortly after a power failure. Hank' body is found severely burned, Diana speculates that Hank used a flare to burn himself before the alien could get to him.
Diana then comes under suspicion when a scrap of torn shirt containing her name tag is found at the camp, and she is locked outside the base, on Mars' surface without much oxygen. Somehow finding her way back to station without a guide line, Diana breaks into a storage room and threatens the rest of the crew with a remote detonator. In the course of the standoff, Chester suffers a heart attack. When Ana attempts to revive Chester by defibrillation, Chester's body transforms and kills her, eating her head. Chester's head detaches from his body and the alien uses it in an attempt to escape as the others burn the body, leading Diana to theorize that every piece of the alien is an individual animal with its own survival instinct. She then burns the head with his flamethrower. Accessing the ship's computer, Diana discovers that the base's corporate employers had known about the Russian excavation all along, and that Johann had been placed aboard with a secret order to return the creature to them, even at the expense of the crew's lives; it was he whom destroyed the blood supplies, that had willingly allowed the infected chimpanzee and Marco to enter and that murdered Hank in order to hide the truth when he discovered Johann's intentions. Johann almost suffocates her, but Jacques intervenes and decapitates him with a blow from a fire extinguisher, revealing Johann to be an android. Before Jacques incinerates him with the flamethrower, Johann smugly predicts that the other crew members will not survive. Diana and Jacques then set out to take Cheol out of the room she had been locked in to escape, only to find that she has escaped by tunneling her way underground. They follow the path and discover that not only had Cheol been assimilated, but she had been constructing a small flying vehicle of alien design underneath the tool shed in order to reach and infect the mainland.
They return to the surface to witness Childs inexplicably abandoning his post at the main gate, followed by the facility losing power. Realizing that the creature now wants to be buried again so a future rescue team will find it, the remaining crew acknowledge that they will not survive and set about destroying the facility in hopes of killing the creature. While arming the station's self destruct system to take their chances in the shuttle, Jacques is killed by the infected Cheol. Alone, Diana prepares to detonate the ship in a distance when the creature, larger than ever, emerges from beneath the floor. Diana attacks it with a flamethrower, which damanages the self destruct system and starts a chain reaction that destroys Cheol and the entire facility. Diana finds the alien is gone and narrowly escapes in the shuttle as the station explodes.
As she prepares to enter stasis aboard the shuttle on her way back to Earth, Diana discovers that the creature, now a fusion of all whom it infected, in fact stowed aboard the shuttle with her. She puts on a space suit and opens the hatch, causing explosive decompression which forces the monster out of the open doorway, but it hangs on. Diana shoots it with a grappling gun and the impact propels it out; in the process, the gun is ripped from her hands and catches in the closing door, tethering the wounded alien to the shuttle. It attempts to crawl into one of the engines, at which point Diana activates them and incinerates it, blasting the alien into space. She broadcasts a distress call, and puts herself into stasis for the return trip to Earth.
- Brie Larson as Diana Williams
- Tom Cruise as Kennedy "Ken" Gilligan
- Oscar Isaac as Marco Santiago
- Alice Braga as Ana Ramos
- Omar Sy as Jacques Du Lac
- Sharlto Copley as Chester Briggs
- Claudia Kim as Cheol Han
- Chiwetel Elijifor as Henry "Hank" Zavimbe
- Christoph Waltz as Johann Adler
- Aleksandr Aleksandrov as Igor
- Alexey Nilov as Androvich