It was produced by Arnold Houghland and Lou Rusoff, directed by Ray Milland, who also stars with Jean Hagen, Frankie Avalon, Mary Mitchel, and Joan Freeman.

Harry Baldwin, his wife Ann, their son Rick, and daughter Karen leave suburban Los Angeles at sunrise to go on a fishing trip to the Sierra Nevada wilderness, bringing with them a small camping trailer.

After a couple of hours on the road, Harry and Ann are startled by a series of unusually bright lights, accompanied by a radio station going to static.

Tuning through stations, they hear a sporadic news report broadcast on CONELRAD that hint at the start of an atomic war, confirmed when the Baldwins see a large mushroom cloud from a hydrogen bomb rising over Los Angeles, now many miles away.

The family attempt to return home and rescue Ann's mother, but Harry soon realizes that the roads will be clogged by panicked people, and what is left of the city will be saturated in atomic fallout.

The Baldwins stop to buy supplies at a small town off the main road, which has not yet been inundated by refugees from Los Angeles.

Harry attempts to purchase tools and guns from hardware store owner Ed Johnson with a personal check.

However, Johnson believes only Los Angeles has been hit, and the government remains intact, so he insists on following state law and withholding the guns for 24 hours while Harry's checks are verified.

The Baldwins leave their camp to find a doctor named Strong, whom Marilyn knows in the nearby town of Paxton, California.

The soldiers watch the Baldwins leave and note that the family is among the "good ones" who escaped radiation sickness by being in the mountains when the atomic bombs exploded.

[1] Michael Atkinson, the film critic for The Village Voice, liked the film and wrote in 2005, "This forgotten, saber-toothed 1962 AIP cheapie might be the most expressive on-the-ground nightmare of the Cold War era, providing a template not only for countless social-breakdown genre flicks (most particularly, Michael Haneke's Time of the Wolf) but also for authentic crisis—shades of New Orleans haunt its DVD margins...the movie is nevertheless an anxious, detail-rich essay on moral collapse.

scrupulously avoids any scenes requiring more than minimalist production values yet still delivers on its promise, allowing audience imagination to expand upon the narrow scope of what's actually on the screen.