Space Mouse is captured by the cats of Felinia and is exiled to the planet "Nothing," which is just a round ball. The surface turns out to be a shell covering the planet of the "Caution People" who are afraid of everything.; Dr. Rocket invents the "Lunar Leaper," a pogo-stick designed to hop from planet to planet. Space Mouse is picked to test it.; The Royal Treasury is empty and collection agents are repossessing the King's rocket fleet and other possessions. Space Mouse comes up an idea to open the castle for paid tours to raise funds.; On a riverboat to River City, Inspector Willoughby has to keep a crook from stealing a bag of money he is transporting.; King Size sends Space Mouse to fetch some Plutonian Pickles for lunch, but Space Mouse gets arrested for exceeding the speed limit.; Space Mouse goes to a supposedly uninhabited planet to practice the trumpet.; Space Mouse's batted baseball knocks a hole in a spacecraft's windshield and also in the driver's helmet.; Space Mouse is testing a new rocket when he sees a kite flying past.