Hetty Birtwisle has been brought up by adoptive parents in the Fens; after a beating by her father, discovering that she was adopted, she flees to Birmingham where she has learnt she was born and alters her surname to Beauchamp.

Hetty Beauchamp comes across several characters from Carr's other novels in the boarding house in which she lives, including Emma Foxberrow, a teacher in The Harpole Report and Edward Peplow, from A Day in Summer.

Carr was offered an advance of £5,000 for the novel, including paperback rights, but as this was the same amount that he had been offered three years earlier for The Battle of Pollocks Crossing, he decided to publish it himself.

However he based postage mistakenly on the cost of sending a Penguin paperback, and What Hetty Did was printed on superior paper with card covers, so it was heavier than expected and he lost money on postage.

[1] The story was adapted by Ellen Dryden for BBC Radio 4's Woman's Hour Drama in 2004.