A reporter investigates a series of spaceship disappearances and is captured by primitive aliens. He forces them to free him by pretending that a simple gadget is a powerful bomb.; A chief of a Pacific island tribe finds aliens in a volcano preparing to conquer Earth. He thinks his people will not believe him, so he instead agrees to sell the island to the US for nuclear tests, which destroys the aliens.; A supercomputer and its army of robots enslave humanity, but it is stopped when a janitor unplugs it.; A prison colony grows into a thriving society and forgets its origins, while the mother planet becomes a peaceful utopia before being devastated by invaders. The mother planet was Mars, and the prison planet Earth.; An alien lands on Earth, but cannot be understood. The humans attack it out of fear, and finally drop a nuclear bomb on it. The alien leaves, not out of fear, but because its attempt to make peaceful contact has shown that humans are barbarians.