George says no to having Astro, a stray dog, but thinks a robot dog will be better for the family, so gets 'Lectronimo. When a burglar breaks in, though, Astro proves to be the better dog.

George is too busy at work to help Elroy with his Space Cub training, but when his boss's son is in the same troop, he is forced to go on a hiking trip with them to the Moon.