A letter from the remote and land of Australia turns the Robinson household upside down.

Becca Robinson has no doubts about the exciting move, but her older brother Fritz is afraid it will devastate his career plans.

As the Robinsons travel down the Rhine, a riverboat con man finds Becca easy prey. A famous diva helps to unmask the swindler.

The Robinsons set sail from England, and their adventures at sea begin. Jack's antics cause problems with fellow passengers.

Fritz's new friend Emily is distressed by a family quarrel and may have to leave the ship at the next port.

The shipboard Christmas pageant is cut short by a violent storm. As the elements rage, the ship runs aground, and passengers escape in lifeboats.

Fritz narrowly escapes drowning, and after a treacherous night on the damaged ship, the family builds a raft to escape to an island on the horizon.

Accompanied by the captain's dog Brewster, the Robinsons arrive on the island and set up camp.

When Brewster discovers his drowned master washed onto the beach, Fritz is especially moved because the captain died saving his life.

While Fritz and Ernest scale the mountains, the rest of the family scouts for supplies, and Becca's playfulness almost ends in disaster.

Fritz and his father are overdue, and jackals stalk the forest. At night the beasts attack, and Mother, though terrified, fights them off with a rifle and torches.

When he realizes they are stranded on an isolated island, Fritz gives up hope. Then a poisonous insect bite threatens his eyesight.