Unlike Stewart's earlier mystery/romance novels, Thornyhold does not have any references to contemporary places and events. It has the character of a modern fairy tale, an updated Sleeping Beauty. Many fairy tale stereotypes are used — the fairy godmother who mysteriously appears and always seems to know what Gillian is thinking, the animals that bring messages, even Gillian's bleak early childhood that echoes the trials of Cinderella and other suffering fairy tale heroines.

The woods and landscapes surrounding Thornyhold are romantic settings, peopled by benign rustic characters.

The lovers, rustics and fairies of Shakespeare's A Midsummer Night's Dream (c.1591-1596) would have been right at home in the forest surrounding the old house of Thornyhold.