An eclectic group of characters set sail on Captain Lansen’s leaky cargo ship in an attempt to escape their various troubles. When a violent storm strikes, the ship is swept into the Sargasso Sea and the passengers find themselves trapped on an island populated by man-eating seaweed, giant crabs...
Four cousins meet a new friend who has strange powers over all the animals on Whispering Island. After discovering the crusader's treasure, they are imprisoned in a flooded dungeon.
Four children go to stay in a cottage near the sea where they meet Wilfred, an orphan who can attract animals by playing his pipe. They explore a nearby island for treasure and find the owner is being robbed by his gamekeepers. Brought before Sir Hugo the children convince him of their story but...