Earthbound youngsters will find much mirth in this topsy turvy trip through space. Does life exist on Earth? Young Matthew Looney and his famous space cadet uncle aren't sure, but they bravely embark on an earthly expedition in their rocket ship Moonbeam II to find out. Disobeying regulations, Matthew stows away his favorite pet Murtle, who falls to Earth, is retrieved and is brought back to Moon alive. In an exciting court martial, Matthew challenges current scientific belief that oxygen is fatal, and proves through Murtle that life may very well exist on Earth. What life on the Moon is like is cleverly described and Gahan Wilson's comic pictures of Moon people add to the general merriment.