Unearthly Stranger

Davidson, the narrator, fears for his life as his predecessor dies under mysterious circumstances just after making a major breakthrough. The official cause is described as 'an explosion inside his brain' and is being withheld by Major Clarke. The surviving scientists press on, driven by the possibility of spaceflight powered by mental concentration.

Davidson marries Julie, his Swiss wife, who quickly reveals a string of unusual abilities and behaviors. Clarke suspects she may be an alien, noting she sleeps with her eyes open, never blinks, has no pulse, and can handle extreme heat with her bare hands. After frightening a schoolyard, it becomes clear her tears burn when she cries.

Clarke conducts a thorough background check and discovers Julie never existed before meeting Davidson. This revelation deepens the mystery: if she is truly an alien, she would have no verifiable past.

For security reasons, Davidson is removed from his lab duties, leaving him with time to revisit the unresolved problem his predecessor left behind. He is effectively sidelined, but not silenced, in the race for the breakthrough.

Against orders, Davidson recovers the lost formula relating to the spaceflight breakthrough. Clarke confiscates the notes, attempting to suppress the evidence of the progress.

Clarke is struck dead in the same mysterious way as the predecessor, suggesting a pattern of sabotage connected to the breakthrough. The death underscores the peril surrounding the project.

Julie finally admits she is an alien sent to kill her husband and that she must leave because she has fallen in love with him. Her confession confirms the looming danger around the project.

Despite his pleas, she vanishes, leaving only an empty dress behind. The absence hints at an unseen force at work and the collapse of their fragile bond.

Davidson rushes to his office to record a tape that narrates the events and warns that aliens would try to stop the breakthrough. The act preserves his side of the story and serves as a final warning.

Davidson's secretary arrives as another alien to finish the assignment. A struggle ensues as her concentration wavers, and she falls backwards out a window, landing only an empty dress on the pavement.

Scientists rush downstairs only to be quietly surrounded by a crowd of grim-visaged women who are chillingly aliens. The moment confirms a larger alien presence and intent behind the project.

The film closes with the implication that aliens intend to halt the breakthrough entirely, leaving the scientists facing an uncertain future. The world glimpses a broader threat beyond the immediate experiment.