The X-20, an experimental space interceptor, disappeared off the radar screen for 24 hours before crash landing in the Mojave Desert. One of the crew, Major William Gart, is taken to the hospital for treatment of a broken leg. Colonel Forbes, one of the other two men, goes to see Gart, who wants to know what's going on in the outside world. Forbes, nervous, assures him that the ship is fine. Gart wonders if he's drunk and comments that he looks hungover. They share a pack of cigarettes and Forbes says that something has happened that he doesn't understand. He closes the door and then asks Gart when he left the hospital. Gart wonders what he's talking about and Forbes says that he left the hospital yesterday at 9:30. He asks who he left with, and Gart says that no one left with him. Forbes then shows him a newspaper, saying that two men crashed in the desert. The picture shows Forbes and Gart.
Forbes goes over all the information in the newspaper article, and Gart insists that it's right. However, Forbes says that there were three of them: the two of them and Colonel Ed Harrington. There were three beds in the room, and Gart points out that there are only two beds. Gart has no idea who he's talking about and Forbes says that he and Harrington were discharged the previous day. Gart insists that there were only two men on the ship, and doesn't know anyone named Harrington. Forbes relates every single thing that happened and swears that it all happened.
Forbes describes how he and Harrington talked to Gart, wished him well, and left to go to a bar that night. As Forbes talked with a woman, Harrington looked up in the mirror and appears shocked. When Forbes offers a toast, Harrington drops his beer and Forbes wonders if he's sick. Harrington says that he feels unusual, as if he doesn't belong there. He says that if he let himself go, he thinks that he'd disappear. Harrington goes to the phone booth to call his folks in Des Moines, IA. A few seconds later, he calls Forbes over and tells him that he called home… and his folks have no idea who he is. His mother told him that she didn't have a son named Ed Harrington. They figured Harrington was some kind of practical joker. Harrington thinks it has to do with the feelings he's having, and wonders if something or somebody made a mistake and let us come back when they shouldn't have. Forbes tells him to settle down and goes to get him a drink. As he goes, he notices a newspaper on the table… and its sys only he and Gart returned. When Forbes turns back to the phone booth, Harrington is gone. He goes back to the bar, but no one remembers Harrington. The beer that Harrington dropped has vanished as well.
Forbes goes home to call the base, and his wife Amy comes in. She's mad that he didn't meet her at the bus station to pick her up when she arrived. Forbes remembers that he sent her a wire to meet him and Harrington. He gets the note but it no longer refers to Harrington, and she has no idea who Harrington is. Forbes calls the Air Force base but no one there knows who Harrington is, either. He thinks it's some kind of practical joke and figures Harrington is still at the bar. He turns and runs off into the night and goes back to the bar, but there's no one there. Forbes crawls into the phone booth and begs Harrington to come back.
Back at Gart's room, Forbes says that after that, he ran down the street like a crazy man. Gart insists he's never heard of Harrington. Forbes figures that something let them slip through and come back to Earth, and now the same force is bring them back. He begins to feel the same disappearing sensation and turns to the mirror. He and Gart stare in horror as Forbes' reflection is no longer there. Forbes runs out the door and Gart goes after him… only to discover that he's disappeared. Gart calls out to a nurse but she has no idea who Forbes is. He turns back to the room but now there's only one bed. The nurse gets him into his bed and goes to call the doctor. Gart looks at the newspaper, which now says that only one pilot returned in the X-20.
A minute later, the nurse returns with a medical officer. She confirms that the room is empty and can be used for incoming malaria patients. Gart has disappeared without a trace, and with no trace of his existence left behind. And in a hanger on the base, the X-20 disappears without a trace.