On Christmas Eve in the year 2287, Jack Collins, a freshly appointed Overseer, is excited to celebrate his first holiday in charge of Vault 71. But just days before, a mysterious virus sweeps through the community, killing every inhabitant but Jack. Unable to accept the mass death around him, Jack dissociates entirely from reality.

The film takes place in Sunset Valley during a sudden undead uprising. As the town falls into chaos, most residents go into hiding. But Brittany, a teenage girl home alone while her parents vacation for their 20th anniversary, chooses a different path. Devastated by the loss of her boyfriend Chad — who died just two months prior in a car accident — Brittany gears up with her father’s tools and sets out to the town cemetery. Convinced that Chad might have been among the reanimated dead, her mission is not survival, but reunion.