The Swiss Family Robinson, with Emily Montrose as passenger, sail for Australia with a cargo of gunpowder. Capt. William Robinson in command, Sir Charles Leicester, wayward son, sea rover and pirate chief is also aboard. He and Frederick Robinson are rivals for Emily's hand. During a storm a fire starts near the powder. Sir Charles and the crew take over the command of the ship. In the hold, Frederick is striving to keep the kegs from the flames. The ship founders, and the pirates abandon ship. After a calm the Robinsons make their way to a distant island. The island is the pirate's base and inhabited by followers of Sir Charles. The Swiss Family set up a tent and prepare to adjust themselves to their new home. The adventures that follow are many.