A scientist thinks the way to ensure peace among nations is to provide them with a greater threat so he builds an atomic planet mover that brings Mars closer to Earth. The Martians invade and New York city is nearly destroyed. Cap is ordered by the Martian warlord to deliver an ultimatum to Earth's leaders, but Cap visits the scientist's lab instead and powers up the planet mover again so that the planet Mars returns to its previous location. The Martians cannot eat Earth food, and their rocketships cannot travel the distance back to Mars, so they choose to die in space. The Earth nations go back to threatening each other and Steve says to his class that this is a lesson never to try and rid yourself of an evil by way of a greater evil.