Clegg Forbes arrives at a military hospital to visit his friend and co-pilot Major William Gart. The two had recently piloted an experimental spaceplane, the X-20 DynaSoar, on a mission that took them 900 miles beyond the confines of the Earth's atmosphere, the first time man had been that far out in space. During their voyage the men blacked out for four hours and the craft itself disappeared from radar screens for a full day before reappearing and crash landing in the desert, leaving Gart with a broken leg. Gart inquires as to the status of the plane, but Forbes is clearly agitated and asks Gart if he remembers how many people were on the mission, producing a newspaper with a front page showing the likenesses of the two men and a headline stating that two astronauts were rescued from the desert crash. Gart confirms that only he and Forbes piloted the plane, but Forbes insists that a third man – Colonel Ed Harrington, his best friend for 15 years – accompanied them. In a flashback, on the previous morning, Harrington and Forbes are shown joking with Gart as they are discharged from the hospital after passing their physical exams, leaving the Major to recuperate alone. The same newspaper that Forbes would later show Gart is present but, accompanied by a photo depicting a crew of three, the headline instead asserts three astronauts were recovered from the crash of the X-20. Harrington and Forbes visit a bar downtown. While there, Harrington is suddenly overcome by a feeling that he no longer "belongs" in the world. Disturbed, he phones his parents who tell him they have no son named Ed Harrington and believe the person calling them to be a prankster. Harrington then mysteriously vanishes from the phone booth and no one in the bar but Forbes remembers his existence. Increasingly desperate, Forbes searches for any trace of his friend but can find nothing in the bar. His girlfriend, Amy, does not remember Harrington, and neither does his commanding officer. Returning to the closed bar, he breaks-in by smashing through the glass door looking for Harrington, calling his name repeatedly. He then breaks down in the phone booth where his friend vanished. Back in the hospital in the present, Forbes finishes recounting the story to Gart and is dismayed by his friend's claim that he doesn't know anyone named Harrington. Forbes then glances at a mirror and discovers he casts no reflection, causing him to flee the room in terror. Gart tries to hobble after him only to find that Forbes has disappeared. Calling the duty nurse to ask if she saw where Forbes went, Gart is stunned by the nurse's claim that nobody named Forbes has been in the building and that Gart was the only man who was in the hospital room. After getting back into bed, he notices the newspaper headline has changed. It now says that Gart was the sole pilot of the X-20 – all mention of Forbes, including his photo, is gone. Horrified, Gart also disappears. An officer enters the building and asks the duty nurse if there are any unused rooms available to accommodate new patients. The nurse takes him to the now completely-empty room which hosted the three astronauts, telling him that it has been unoccupied. The officer affirms that it will be appropriate for malaria patients and orders that new beds be installed. The hangar which previously housed the X-20 is then shown, with the sheet that covered the craft lying on the ground. There is no trace of the plane.
