The adventures of Frank and Buster, two intrepid young koalas who fly around the Australian outback on a special mission to help other creatures in need. George loves delivering the mail to all his outback friends but one day, George has so much mail to deliver that he gets in a bit of a flap. The Koala Brothers offer to help George by helping him deliver some of the mail using the plane. To show how much they appreciate him, Frank and Buster lay on a surprise party for George.