The survivors build a stockade and explore the island. The island, their first place of rescue, appears to the survivors of the Mary Jane as a prison. The castaways will soon realize that this is one of the many South Sea Islands located far away from the Australian mainland.

A cyclone hits the castaways' camp, bringing gold from the wreck of the Mary Jane---and destruction. A storm destroys in one stroke everything that the castaways had painstakingly built up in five weeks. Jan Lindberg is proposing to build a weatherproof hut. However, Billy, Irving and Holt are with their thoughts somewhere else: they have found a few pieces of gold: the remains of the ship's treasury.