The film opens with a
CIA internal memo about Arlington Steward, a man who has recovered from severe burn wounds and is delivering units related to the Mars project. Set in 1976, the story follows Norma and Arthur Lewis, who awaken early one morning to find a mysterious package on their doorstep. Inside is a wooden box with a button protected by a glass dome, a key, and a note stating that Mr. Steward will visit at 5:00 pm. Norma and Arthur have breakfast with their son, Walter, before Arthur heads to work at
NASA, where he works in optics and was involved in designing the camera for the Viking Mars probe. Arthur learns he has been rejected from the astronaut program due to failing the psychological exam. Norma, who teaches literature at an elite private school, reveals her disfigured right foot to her class during a discussion on
Jean-Paul Sartre's vision of Hell. She learns from her boss that her tuition discount for Walter's school is being revoked, causing financial concern. Later, Arlington Steward, a man with a severely disfigured face, arrives at their door as promised. He presents an offer: if they press the button, someone they do not know will die, and they will receive one million dollars. Arlington leaves them with 24 hours to decide. After much deliberation, Norma impulsively presses the button. Arlington returns and gives them the promised money, implying that someone close to them may die as a consequence. Arthur attempts to return the money, but Arlington leaves abruptly. Later, Arthur and Norma attend a wedding rehearsal dinner, where Arthur encounters a student of Norma's and sees a box similar to the one left on their doorstep, containing a photograph of Arlington. Arthur's investigation into Arlington's background reveals his car is registered to the
NSA. Concurrently, Norma receives a cryptic warning from a stranger at a supermarket, instructing her to look up a library call number and not trust Arthur. Arlington chastises Norma for involving the police, as Arthur had asked Norma's father, a police officer, to run Arlington's license plate. At home, Arthur's encounter with their babysitter, Dana, reveals she is not who she claims to be. She directs him to look in the mirror for answers before disappearing mysteriously. Further, Arthur discovers Arlington's photo in a picture from his work at NASA. Arthur and Norma separately visit a library, each following clues leading to Arlington. Arthur, guided by Arlington's wife, navigates through three water gateways, choosing the correct one based on a prior hint. Norma, guided by Arlington, reflects on her disfigurement and experiences a moment of emotional connection with him. Norma and Arthur reunite at home, where Arthur emerges from the water portal, and they find Walter demanding answers. At a wedding, their son is kidnapped, and Arthur is abducted by a former NASA employee, who reveals he faced a similar choice between his wife and daughter. Arthur is shown a manual and water portals but is interrupted by a
Santa Claus figure before being struck by a truck. Arthur emerges from a NASA warehouse, surrounded by military personnel. Back home, Arlington offers them a final choice: live with their million dollars and a deaf-blind son, or Arthur can shoot Norma, restoring Walter's senses and securing the money for his future. They learn Arlington's employers are testing humanity's worthiness. Norma and Arthur decide to sacrifice Norma. After she is shot, Walter's senses are restored, and Arlington delivers the million to another couple who have pressed the button. The film concludes with Arthur being taken away by authorities, indicating the cycle of testing will continue. ==Cast==