After escaping from the Sea of Trolls, the apprentice bard Jack plunges into a new series of adventures, traveling underground to Elfland and uncovering the truth about his little sister Lucy.
Two years after their adventures in The Land of the Silver Apples, the apprentice bard Jack and his Viking companion Thorgil confront the malevolent spirit of a vengeful mermaid and begin a quest that casts them among the fin folk of Notland.