The story kicks off in space, where introductory title cards highlight the significant advancements in space travel technology and the alarming overpopulation on Earth. By the year 2174, the spaceship Elysium is launched, soaring through the cosmos. On the ship's bridge, officers receive a chilling message from Earth: "You're all that's left of us. Good luck, God Bless, and God speed."
As the narrative unfolds, Bower (Ben Foster) awakens from his hyper-sleep pod, plagued by claustrophobia in the cramped quarters. Breaking free from the pod and detaching the invasive tubes, he notices a sequence of numbers inked on his arm. Peeling away the dead skin, he panics at the stark realization of his solitude. He stumbles upon a locker with his name, slips on some clothes, and finds an image of a woman, which adds to his confusion. Nearby pods reveal that Cooper is missing, while another pod still houses Payton (Dennis Quaid). Desperately, Bower attempts to rouse Payton from his slumber, banging on the pod to no avail. A formidable power surge jolts the ship, awakening Payton. Both men, suffering from memory loss due to General Anesthesia, grapple with the mysterious circumstances of their mission and the ship's purpose.
With Payton identified as a Lieutenant and Bower as a Corporal, they realize they are alone, marked by the numbers on their arms indicating their respective groups. As a power surge rattles the ship again, Bower deduces his role as an engineer and learns that the reactor requires immediate attention. Payton manages to access the command center with auxiliary power but faces silence when calling for help. Hearing a noise from the vents prompts Payton to urge Bower to investigate while he stays back to provide guidance.
Navigating the labyrinthine vents becomes a daunting task, filled with anxiety and panic. Bower ultimately finds himself in a storage compartment, where he discovers Cooper's decomposing corpse, deepening his dread. As he wanders the dimly lit corridors, he encounters a woman named Nadia (credited as Antje Traue) who is frantically trying to access a door. Their brief interaction turns hostile when she holds Bower at knife-point, stripping him of supplies. Amidst this confrontation, ear-piercing screeches echo, causing Nadia to flee, leaving Bower confused.
The ensuing chaos reveals humanoid creatures known as The Hunters who launch a violent assault on their surroundings. Seeking safety, Bower hides, but soon becomes aware that something inhuman is aboard the ship. As Bower and Payton's memories slowly return, they grasp the gravitas of their situation: they are not in a cargo ship but rather the cargo itself, en route to an Earth-like planet called Tanis.
In a series of frantic events, they encounter a variety of characters, including Shepard (Norman Reedus) and Mahn (Cung Le), who reveal harrowing truths about their existence and the horrors they face. The trio becomes embroiled in terrifying encounters with the creatures while grappling with their own dwindling sanity as Pandorum, or space madness, looms ominously overhead.
Bower's determination to reconnect with his memories and find his missing wife intensifies as he rallies those around him, including Nadia. Through harrowing trials, Bower gradually disrupts the despair and unravels the layers of fear, ultimately drawing strength from camaraderie. The remnants of hope flicker as they devise a plan to restart the reactor and restore power to the ship, although dark revelations emerge about the nature of their mission and the twisted legacy left by previous passengers.
As the stakes heighten and confrontations with Gallo (Cam Gigandet) escalate, the group perseveres against mortal threats while battling the psychological demons that come with their journey. Time runs thin as they scramble to activate the reactor before it's too late, culminating in a chaotic and desperate race for survival.
In the gripping climax, the intricate web of relationships and betrayals is revealed, as the true nature of the Elysium's fate and its eternal role in shaping humanity's future unveils itself. After a harrowing struggle, Bower and Nadia manage to escape into the open waters of Tanis, breathing life into the notion of rebirth and hope. As the film concludes with the uplifting dawn of a new era, it encapsulates the indomitable spirit of survival and the relentless pursuit of redemption in a universe fraught with darkness. A new beginning emerges as humanity's journey on Tanis begins, setting the stage for future discoveries.
