Scientists led by American Cole Hendron work desperately to build an atomic rocket to transport enough people, animals and equipment to Bronson Beta to save humanity from extinction.

Tidal waves sweep inland at a height of 750 feet (230 m), volcanic eruptions and earthquakes add to the deadly toll, and the weather runs wild for more than two days.

Five months before the end, desperate mobs attack the camp, killing over half of Hendron's people before they are defeated; the defenders take up the rocket, hover, and blast the enemy with its deadly exhaust.

With the rocket tube breakthrough, the survivors are able to build a second, larger ship that can carry everyone left alive (instead of only 100 of the roughly thousand people Hendron had recruited).

[a] Jack Williamson's 1934 short story "Born of the Sun" also used the concept of a scientist and his fiancée escaping the destruction of the Earth in a hurriedly constructed "ark of space".

[3] In 2012, the British composer Nigel Clarke wrote a large-scale work for brass band inspired by the film and likewise titled When Worlds Collide.