In a world reshaped by a global zombie catastrophe, the 1980s bring a sweeping crisis that claims an estimated 100 million lives. The disease demands a daily medical dose to stay in check, and missing even one treatment sends the infected spiraling into a rapid, irreversible feral state. The crucial medicine can only be harvested from dead feral zombies, which feeds constant rumors that supplies will soon run dry. The infected, known as the returned, face widespread prejudice and violence from a frightened, vigilant society.
Dr. Kate dedicates herself to caring for the returned and funds ongoing research to manufacture a synthetic cure. To secure the future of treatment, she secretly stockpiles black-market doses, living in a state of anxious preservation. Her husband Alex—a music teacher—has himself become infected after trying to assist a man who seemed to be having a seizure. When Alex reveals his status to his best friend Jacob, the news is met with surprising acceptance, a glimmer of humanity amid fear.
As protests turn violent and authorities advance quarantine measures intended to suppress dissent, Jacob and his wife Amber invite Kate and Alex to shelter with them outside the city. The uneasy safety is punctuated by near misses: Alex narrowly escapes an attempted murder and a police sweep that could have ended their precarious refuge.
Trouble compounds when Kate’s informant is found dead, and suspicion quickly falls on Amber. Kate tasks Alex with checking the couple’s supply of the crucial medicine. He discovers a single dose and a remorseful note from Jacob, revealing that Amber has herself become infected and that the rest of the supply has been used. With only one day left before death would turn him, Alex becomes desperate to find another source.
Back in the city, Kate goes to the hospital chief with a grave dilemma. The chief grants access to the hospital’s entire stash, hoping to avert a broader crisis. Yet a violent confrontation erupts when a parent of an infected child attempts to steal the container, and the struggle shatters the precious supply, leaving nothing usable behind.
Grief-stricken, Kate returns to Alex, who has chained himself to a wall in a quiet act of final defiance against the disease. As the symptoms surge, he pleads for mercy, asking Kate to shoot him in the head. Her own traumatic memory—triggered by her mother’s infection—visibly complicates the decision, and she ultimately ends his life off-screen once he has turned. She then journeys back to the city to settle her affairs, only to be told by the hospital chief that researchers have finally succeeded in creating a synthesized treatment—an outcome that fills Kate with both sorrow and reluctant relief.
Months pass, and the closing image follows a pregnant Kate as she contemplates a shocking turn of vengeance: she prepares to ambush Jacob and Amber during a book tour, signaling that the struggle over infection, loyalty, and survival is far from over. The narrative lingers on the toll of the plague, the costs of hope, and the heavy burden carried by those who fight to keep others alive in a broken world.