When Angelino Jack Robinson gets a new job in Australia, he decides to take his wife Anna, sons Shane and Todd, and daughter Elisabeth 'Lizzy' by sailing yacht from Hong Kong to Sydney. The gun he gets, thrown in by Sheldon Blake, proves disabled, and for a sinister reason: near Borneo, Blake's men turn up to capture them. The family escapes but loses the yacht on a reef. They build a cool camp on an island. But the pirates keep coming back, and the boys discover why: he hid a treasure in the yacht. Shane is also discovered and captured in more than one way by French plane-wreck survivor Françoise, who later teams up with the family.