A widow, her infant daughter, and a young orphaned boy are cast off from the ship they are travelling on, and are stranded on a deserted island. The widow tries to raise them to be civilised, but soon gives up, as the boy, called Richard, was born and raised by young lovers on this same island, and he influences the widow's daughter, Lilli. They grow up, and the widow teaches them from the bible, as well as from her own knowledge, including the facts of life. When they are about eight, she dies, leaving them to finish raising themselves. They grow up, and as young adults, they fall in love and exchange formal wedding vows and rings. Soon after, a ship arrives at the island, carrying unruly sailors, a stuffy captain, and his beautiful daughter Sylvia. They offer to bring them back to civilization. Sylvia tries to steal Richard from Lilli, but as tempted as he is by her strangeness, he realises that Lilli is his heart and soul, upsetting Sylvia. Richard is forced to lure a sailor to his death on the reef, or be killed by him. He apologises to Lilli for hurting her, and she reveals that she is pregnant.
