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. When George forgets to screw the lid of his flask on properly, the tea spills inside his satchel and makes the addresses on his letters and parcels unreadable. The Koala Brothers help George discover who they belong to, and work out who owns all the mail items except one, which turns out to be a special commendation for George himself.