Set just after the American civil war, businessman and inventor Victor Barbicane invents a new source of power called Power X. He plans to use it to power rockets, and to show its potential he plans to send a projectile to the moon. Joining him for the trip are his assistant Ben Sharpe, Barbicane's arch-rival Stuyvesant Nicholl, and Nicholl's daughter Virginia. Nicholl believes that Power X goes against the will of God and sabotages the projectile so that they cannot return to earth, setting up a suspenseful finale as they battle to repair the projectile.

A murderous thief on the run with stolen loot forces a poor rancher to guide him across the desert into Mexico. Accompanying them is the rancher's wife, who happens to be the killer's former girlfriend.