Larry Martin (Judd Holdren), a leader in the Inter-Planetary Patrol, detects a rocket coming to Earth. He takes to the air in his rocket suit and helmet to investigate and discovers two Martian invaders, Marex (Lane Bradford) and Narab (Leonard Nimoy). Since Mars is now orbiting too far from the Sun and its ecology has been dying, the Martian invaders want to swap Earth's and Mars' orbits, so Mars will then be closer to the Sun. They plan on achieving this by using hydrogen bomb plans stolen from Earth scientists to cause the two planets' orbits to swap, using specifically placed atomic explosions on both worlds.
