In 2039, Duncan tends the solar panels while his father roams a quiet library, and they shelter in a bunker Duncan built after predicting a catastrophe. The shelter runs on a dedicated oxygen generator that keeps their home habitable, a fragile lifeline as the outside world grows harsher and oxygen levels slip toward dangerous lows.
Duncan’s watch shows the oxygen continuing to fall. He radios his father to hurry toward the bunker, but a tragic accident seals his fate, and Duncan returns home to tell his wife, Maya, Jennifer Hudson, and his daughter, Zora Quvenzhané Wallis, about the loss. He resolves to bury his father the next day alongside his mother, a decision Maya objects to, arguing the burial would be miles away from the bunker and could bring danger to the living they protect.
That night, the oxygen generator signals a breach in the system, hinting that more trouble is looming. The following day, Duncan shares a quiet, hopeful moment with Zora, handing her a book and promising a full report on his mission when he returns.
Five months pass, and Zora tries to reach Duncan through the radio; there is no reply. Maya and Zora cling to a sliver of hope by tending seeds in soil, trying to nurture life in a world that seems barren.
Then a pair arrives at their doorstep: Tess, Milla Jovovich, and her bodyguard Lucas, Sam Worthington, who claim they come from Philadelphia where about 25 people survive. Maya is wary, having learned to distrust any claim about Duncan’s allies, yet Tess insists she worked with him and seeks to replicate the oxygen generator to save others.
Maya, cautious but curious, allows them inside after cuffing them first. Inside, a tense moment erupts when a second armed man rushes in, and Maya and Zora defend their home by firing. Tess stays outside, but Lucas and the others push deeper into the bunker. Tess explains that Micah, Raúl Castillo and he, are meant to be their lookout, and that he is bleeding from an old wound.
As the skirmish escalates, Micah sacrifices more blood than he can spare and dies. With Zora’s quick thinking, an electromagnetic field is used to disrupt Lucas’s entry tool, buying time for Maya and Zora. Tess tries to justify her presence, but Lucas reveals that he never truly knew Duncan. He admits that he overheard Zora speaking to her father about the oxygen generator, and the truth about Duncan’s fate comes to light: Duncan knew the bunker could not hold more than two, and chose to sacrifice himself so his daughter might survive and perhaps unlock a better solution in time.
The struggle continues as the car outside is charged by sunlight and the CO2 level inside the bunker climbs. Maya must hold on, and Zora, now wiser, tries to orchestrate a way out. Lucas slips inside despite the rising hydrogen risk, and in a final, devastating moment he fires a shot that detonates the compromised oxygen system.
With limited oxygen, Maya drives the vehicle toward Philadelphia, looping through the ashes of the crash and calling for help until their supply runs dry. In the aftermath, Maya is taken in by a hopeful community, and Zora is seen back at a new, more advanced oxygen generator, a sign that the world may heal and a new generation might push humanity forward. Earth, finally, begins to reconcile with life as a single growing plant signals renewal and a future in which Zora’s work could save them all.
