A great many incidental characters and places are shared across Masefield's novels, although the fine details of such recurrences are often contradictory from novel to novel. In The Midnight Folk, Kay's great-grandfather is endowed with a great treasure there in other novels the actual nature of the seafaring Harker's relationship to Kay is less clear. One key recurring theme is the nautical visit of a member of the Harker family to the fictional islands of Santa Barbara.

John Masefield threaded a number of common themes through a series of his books even those novels aimed at children shared places, people and storylines with some of his adult novels.

Division within the text is obtained by moving from prose to verse or even song in some places. The Midnight Folk is written as one piece. The guards play little part in the main narrative but have a critical role in the final recovery of the treasure. Kay's toys (known as 'the guards') have been taken away from him at the start of the book, apparently because they will remind him of his parents there is a strong implication that Kay's parents are deceased. It is possible that she represents Masefield's memory of his own mother who died when he was very young. She then reappears at the end of the book as Caroline Louisa, Kay's new guardian. Many maternal characters appear in the book one takes Kay on a nocturnal ride on a magical horse. At one point in the novel he manages to see into the past. Kay Harker has various adventures-sailing on the high seas, swimming with mermaids, flying on broomsticks. There are two other household cats: the main antagonist is Blackmalkin, and he is aided by the mysterious Greymalkin who takes his name from the witch's familiar in the opening scene of Shakespeare's Macbeth. Kay Harker is aided in his quest by various talking animals, most notably Nibbins the cat, who used to be a witch's cat but has reformed. The witches are led or guided by the wizard Abner Brown. Kay's governess Sylvia Daisy Pouncer is a member of the coven. The treasure is also sought by a coven of witches who are seeking it for their own ends. It is about a boy, Kay Harker, who sets out to discover what became of a fortune stolen from his seafaring great grandfather Aston Tirrold Harker (in reality, Aston Tirrold is a village in Oxfordshire). The Midnight Folk is a children's fantasy novel by John Masefield first published in 1927.

The Midnight Folk by John Masefield