Her father, George Heyer, was an author and former member of the Wimbledon Literary and Scientific Society, and as a teenager she befriended the future writers Joanna Cannan and Carola Oman.

Jack discovers his father has died but refuses to take up his role as the new earl of Wyncham, preferring that his brother enjoy the family's privileges in his place.

He desires Miss Diana Beauleigh, a young woman he met in Bath, and is almost successful in abducting her when a disguised Jack encounters them.

Richard gives her permission to leave him and elope with Lovelace, but she realises she truly loves her husband and sees the error in her spoiled ways.

[1][5] In a contemporary review published in 1921, The Times Literary Supplement deemed the protagonist Jack a "fascinating hero of romance" and added that the novel was "a well-filled story which keeps the reader pleased".

But as The Black Moth was a melodrama and a sequel per se would not work in with the plot, she decided to make the new novel stand alone, renamed many characters and made them 'shades' of their former selves for These Old Shades.

In an essay published in 2012, K. Elizabeth Spillman describes the novel as "improbable" and "heavily derivative" but notes characteristics visible in Heyer's other books: the centrality of friendship, seamless action scenes, and a "natural discourse" between the male protagonists.

[8] The Encyclopaedia of British Writers adds that The Black Moth is "typical" of many later Heyer novels, as it has a "historical setting, aristocratic characters, and exciting plot".

[5] As Jack lives as a highwayman, James Devlin also notes themes of violence, suspense and criminality that appear in other Heyer stories such as The Masqueraders (1928) and Faro's Daughter (1941).

[9] Spillman also opines that Diana is the only Heyer heroine to be "unironic [and] untraditional", as the novel is dominated by the doings of its male characters.

[10] In 2012, Diana Wallace wrote of similarities between The Black Moth and the works of Jeffery Farnol and Rafael Sabatini, as well as Baroness Orczy's story The Scarlet Pimpernel.