The adventures of Frank and Buster, two intrepid young koalas on a mission to help other creatures in the outback. Mitzi writes George the postman a letter, but he loses it somewhere on his rounds.
George looks so despondent that the Koala Brothers decide to search for the missing letter. George is so happy to get the letter back that Frank asks everybody to write the postman a letter. When George opens the post the next day, he finds that all the letters are for him!