As the Pilgrim 7 skillfully maneuvers through a perilous meteor storm, Engineer Rory Adams (Eddie Murphy) takes the lead by stepping outside the capsule to skillfully deploy the ship's mechanism, hoping to secure a valuable Martian sample. The tension peaks as the capsule crashes into the mechanism, successfully safeguarding its precious contents for further analysis.
On Earth, a team of biologists, led by Dr. Hugh Derry (Martin Lawrence), is enthusiastic about studying the sample, affectionately labeled "Calvin" by a group of eager elementary school students gathered in Times Square. Initially believed to be an ordinary amoeba, Calvin surprises everyone by sprouting limbs and exhibiting unexpected mobility, leaving the team astounded at the prospect of having a sample that exhibits life.
Meanwhile, aboard the International Space Station, the crew, including Dr. David Jordan (Jake Gyllenhaal), Captain Miranda North (Rebecca Ferguson), Commander Ekaterina "Kat" Golovkina (Olga Dihovichnaya), and pilot Sho Murakami (Hiroyuki Sanada), forms a close-knit unit as they strive to unravel the mysteries of this newly discovered life form. Their personal struggles, such as Sho facing the emotional weight of his wife preparing to give birth back on Earth, add further complexity to their dynamic.
As the crew investigates Calvin, they uncover its astonishing capabilities, which include muscle control, vision, and a functioning brain. The excitement grows, igniting a worldwide sense of wonder as humanity inches closer to comprehending its role in the universe. However, as the lab's technology hums efficiently, a sudden malfunction sends Calvin into a deep comatose state. In a frantic attempt to resuscitate him, Hugh employs an electroshock device. To everyone's shock, Calvin revives with fierce energy, entangling Hugh's hand like a living shackle. Hugh's struggle to escape signals the beginning of a nightmare as Calvin's growth becomes uncontrollable, crippling Hugh before leaving him unconscious.
Calvin, proving to be unstoppable, breaks free of his containment cube, consuming a lab rat in a chilling display of his singular hunger. In the ensuing chaos, Rory leaps in to save Hugh but finds himself ensnared by Calvin's monstrous grasp. Desperately trying to incinerate the creature, Rory runs out of fuel, becoming its next victim and leading to a grisly end as Calvin grows even larger.
The crew, devastated and without proper communication to Earth, turns to Kat for help. Clad in an EVA suit, she braves the Martian void to repair the damage but is met with Calvin's relentless pursuit. The ensuing battle sees Kat fight valiantly to return to the airlock, but despite her efforts, Calvin's grip turns fatal, drowning her in the coolant of her suit.
As Calvin's hunger fuels destruction, the crew finds themselves faced with dire choices: they hatch a plan to sacrifice their oxygen in a bid to trap Calvin, sealing themselves in hibernation pods. Yet, their calculated strategy hits a snag when an emergency oxygen refill leads to fatal consequences, waking the monstrous Calvin, now with an even more terrifying form. With their numbers dwindling, David and Miranda devise a new escape plan, utilizing the tracker in Hugh’s suit to monitor Calvin's movements as they attempt to lure him into a trap.
With Earth Control intervening and a Soyuz capsule dispatched to rescue them, the mission spirals out of control when Sho is cast into the void after an explosive collision at the airlock. With ominous tension mounting, David recalls two escape pods, one designated for Earth and the other for deep space. As chaos reigns with Calvin running rampant, David and Miranda launch their plan, but the unpredictable debris field sends their escape into disarray, allowing Calvin to pursue them.
The climax unfolds with a shocking twist as one of the escape pods crashes into the ocean, where two unsuspecting fishermen stumble upon the horror that is Calvin. Despite David’s frantic efforts to warn them against opening the pod, curiosity overrules caution. The film catapults viewers into a compelling narrative, illustrating how the crew of Pilgrim 7 inadvertently unleashed a dangerous entity from Mars upon humanity. As the story reaches its heart-stopping conclusion, David and Miranda find themselves racing against time, devising plans to contain or eliminate Calvin, but with humanity's fate hanging in the balance, the question remains: can they thwart the threat posed by this aggressive extraterrestrial force?
