The adventures of Frank and Buster, two koalas who fly around the Australian outback in their yellow plane, helping other creatures in need. There's no post for George to deliver but he doesn't know how to spend his free time. The Koala Brothers suggest George takes up a hobby. After realising that Sammy is not the sporty type, they suggest that he takes up stamp collecting. Everyone keeps their stamps for George and soon he has a lovely collection.