A trio of astronauts - Ross (Jack Klugman), Mason (Ross Martin) and Carter (Frederick Beir) - come across what appears to be evidence of intelligent life on an alien world. Upon investigation, it turns out that the ship they spotted is identical to their own ship, except that it has been destroyed in a crash... and inside it are what appear to be their own dead bodies. Further complications arise and the three men end up struggling, sometimes against each other, to try and figure out what's happening to them.
- And I Must Scream: The only mercy is that they don't seem to remember each loop.
- Agent Scully: Captain Ross absolutely refuses to believe that they are ghosts, because there is no evidence that says so. He will prefer to believe that it's the work of aliens before accepting that they are ghosts. Eventually it is deconstructed because his reluctance to believe is what forces the crew, through sheer unrelenting willful denial, to continue to suffer the same situation he refuses to accept forever.
- Curiosity Killed the Cast: There is never information of what killed the crew originally, but the loop always starts with someone seeing "something glinting down there".
- Dead All Along: The whole crew of the ship.
- Determinator: Captain Ross. Unfortunately for his men.
- Discovering Your Own Dead Body: But Ross remains in denial throughout the story.
- Fatal Flaw: Captain Ross' determination to find a rational explanation (well, more rational than the crew being ghosts) even in the face of there being no other explanation, and his indomitable will... in the face of a Heroic BSoD, Ross instead wills the loop to restart through sheer denial.
- Flying Dutchman: Explicitly invoked by Serling in his closing narration.
- Get a Hold of Yourself, Man!: When Lieutenant Mason starts to freak out over their bizarre experiences, Captain Ross punches him in the face and knocks him down.
- "Groundhog Day" Loop: And the narration even compares it to the "flying Dutchman", a never-ending hell.
- Heroic BSoD: Captain Ross at the end, still looking for some rational explanation when Mason and Carter already figured out that they are dead. Unfortunately for the latter two, the result of this breakdown is instead to keep believing that they are alive and the events are some kind of illusion, and that they will keep trying to find an explanation however long it takes... thus triggering the loop.
- Our Ghosts Are Different: Very much looking alive up to and after the incredible reveal, and suffering a "Groundhog Day" Loop for eternity.
- Psychic Powers: Aliens with these are one of Ross' attempts at an explanation of what's going on.
- Riddle for the Ages: How did the crew originally die, if every time they see "something glinting down there", it's the wreckage of their own crashed ship?
- Time Travel: Yet another explanation Ross comes up with.
- 20 Minutes into the Future: In 1997, the E-89 is investigating the feasibility of establishing a colony on the thirteenth planet of Star System 51.
- Undeath Always Ends: Sadly, not the case...