A boy named Edred Arden inherits the title of Lord Arden and the dilapidated Arden Castle. He and his sister Elfrida search for the lost treasure of the Ardens and, with the help of the magical Mouldiwarp, they travel back in time searching for clues. The past events they witness include
The final episode, in which the children rescue their father from a lost civilization in South America, is reminiscent of the legends of El Dorado and other Cities of Gold.
The device of a pair of characters, a brother and a sister named Edred and Elfrida, who travel back in time from Edwardian England, guided by a magical character, Mouldiwarp, always meeting a similar pair of characters in each of the earlier centuries that they visit, is the central plot device in the book. J. R. R. Tolkien's unpublished attempt at a time travel novel, The Lost Road functions in the same way. The Lost Road has father/son pairs named Edwin/Elwin, Eadwine/Aelfwine, Audoin/Alboin, Amandil/Elendil (all meaning "Bliss-friend/Elf-friend" in Old English, Old High German, and Lombardic). Nesbit's Edred and Elfrida, too, have according to the Tolkien scholar Virginia Luling "intriguing[ly]" similar Old English names to Tolkien's paired characters; Edred is "Bliss-counsel", while Elfrida is "Elf-strength".[1]
