In a tense moment inside a small shop, an armed robber demands that the cashier hand over all the money in the safe. The cashier, Michael Dane, empties the register and says there is no safe in the shop. The robber grows more agitated; Cole steps forward, calls him a coward, and dares him to shoot. Michael intercedes and attempts to wrestle the gun away from the robber, only to be shot in the gut. After Cole calls an ambulance, he receives a phone call from a friend inviting him out for drinks, which he accepts on one condition: that it’s not a house party.
Cole is frustrated to learn that it is a house party, and he goes downstairs to drink alone, where he meets Maya, the host. The two discuss an approaching asteroid. Maya suggests that modern stress would melt away in the face of cosmic doom, while Cole argues that such a catastrophe would give life real meaning. The pair share a dance to Maya’s favorite song and soon begin dating. A series of flashforwards depict life in post-apocalyptic Scotland after the asteroid’s arrival as Cole and Maya hide from alien spaceships, interwoven with scenes in the present of their relationship leading up to those events.
As the story unfolds, they discuss children. Cole says he does not want any, and Maya reveals she is unable to bear children. As the asteroid grows closer, Cole asks Maya to marry him; Maya jokingly accepts, and Cole insists that he is serious, and then, with renewed gravity, Maya agrees again. Scientists grow increasingly worried about a collision, and multiple missions to divert the asteroid end in failure, leaving the world on edge. In the flashforwards, Cole and Maya’s relationship deteriorates under the strain of finding food and shelter.
When Maya becomes pregnant, Cole is taken aback and insists that it is cruel to bring a child into such an impending disaster. Maya calls the pregnancy a miracle and keeps the baby despite Cole’s insistence that they discuss abortion. In the flashforwards, their baby is in the care of Maya’s parents, and their relationship has become strained over the issue. Cole accuses Maya of blaming him for their hardships, while Maya counters that his own self-loathing is driving them apart. In desperation, they resort to eating baby food they had saved.
In the present, Michael expresses his dissatisfaction with Cole’s refusal to accept responsibility for his wife’s pregnancy. In a flashforward, Maya and Cole encounter a survivor named Keith Novac, who explains a theory that the aliens have come to purge Earth of overpopulation and leave it a better place for the survivors. He demonstrates attempts to contact the aliens, and Cole tells Keith that their missing child is in the care of Maya’s parents, whom they suspect to have fled the country. Novac suddenly sneaks up and attacks them, and the film shifts back to the present, where Cole and Maya have separated over his opposition to her pregnancy. Maya, who is about to give birth, invites Cole to the hospital.
When Cole arrives, Michael confronts him with a pistol and tells him that he has betrayed his own beliefs. In the face of certain death, Michael says that Cole has abdicated all responsibility and treats his life as meaningless. Envious of the potential for hope in Cole’s life, Michael shoots him. Novac, a doctor, rushes from the hospital, shoots Michael, and works to save Cole’s life. As Cole begins to slip into delirium from his wound, he apparently imagines the various scenes in the flashforwards sparked by the actions of Novac and Michael. Maya calls Cole on his mobile and tells him that the asteroid has missed Earth, and she has given birth to a baby girl. The film ends as Cole lies on a hospital bed, Maya beside him.
