Armed with the knowledge that their mom might still be alive, Kick, Bert, Scruff, and Pin have vowed to find her. They&;ll comb the whole world if they have to! But it seems that her last-known location was closer to home. So with a bewildered Uncle Basti in tow, and their mysterious friend Bone determined to tag along no matter what, the Caddy kids set off for Sydney. Secret tunnels and outback misadventures await!