In 1897, Mrs. Sarah Hargrave, a widow, and two young children are castaway from the ship they are travelling on because the ship's crew are infected with cholera. After days afloat, Kearney, a sailor who has been sent with them, tries to kill the boy because of his excessive crying. Sarah angrily beats Kearney to death with a harpoon and dumps his body overboard. The trio arrives at and is stranded on a beautiful tropical island in the Oceania. Sarah tries to raise them to be civilized, but soon gives up, as the orphaned boy Richard was born and raised by young lovers on this same island, and he influences the widow's daughter Lilli. They grow up and Sarah educates them from the Bible, as well as from her own knowledge, including the birds and the bees. She cautiously demands the children never to go to the forbidden side of the island.