A scientist plans to exchange his brain with a gorilla's so that he can use the gorilla's strength to commit burglaries.; Radzic thinks he will be able to exchange his brain back into his own body, but things don't work out.; Bill and Ruth receive a free television set but it comes from Plutonian invaders who plan to hypnotice Earthlings. The plot is foiled by a crabby landlord who tears down the aliens' antenna.; A man avoids the deadly gaze of Medusa because he is blind.; An aging space pilot is mocked for his slow ship, but when an invading armada approaches Earth his ship is the first to see it. Other ships are moving to fast to see the sneak attack coming, and his warning allows Earth to beat back the invasion, making him a hero and the commander of a new space patrol.; Martians come to Earth to discover if humans represent a threat to them. They question a human using a machine to verify his answers, and find that he is totally free of greed, hatred or deceit. The Martians leave satisfied, unaware that they questioned a mental patient.