It is based on a short story of the same name by Richard Matheson which first appeared in the first issue of the magazine Galaxy Science Fiction in October 1950.

This is the eve of the end.Will Sturka, a scientist who works at a military base, has been producing a great number of H-bombs alongside other staff members who are manufacturing various devastating weapons in preparation for imminent nuclear war.

He plans to bring his friend Jerry Riden, who is trained as a pilot of the spacecraft, along with their wives and Sturka's daughter Jody.

One afternoon, Sturka engages in conversation with a co-worker, Carling, who gleefully tells him that he's heard a rumor the war will start in 48 hours.

At home, Sturka confides in his family, trying to assuage his guilt over helping to create weapons by rationalizing he's only one part in a much larger machine though he recognizes that he still maintains partial responsibility.

Later that night, everyone gathers for a game of cards where Riden reveals that while he was test flying the spacecraft, the military had discovered a small planet 11 million miles away with a civilization similar to theirs—the perfect place to escape.

Riden points out on the ship's viewer their mysterious destination, 11 million miles away—the third planet from the Sun, called "Earth".