Mary Lowther, the pretty young houseguest of the vicar of Bullhampton – Frank Fenwick – and his wife, turns down local squire Harry Gilmore’s proposal of marriage. She knows that, in the eyes of all her friends and relations, a young middle-class girl such as herself, with no financial security, has a ‘duty’ to marry as well as she can.

Marriage to Harry Gilmore represents just such a fulfilment of that duty, except that she does not love him. Despite every attempt to discount this feeling, she cannot bring herself to accept him. Once back at home in Loring with her spinster aunt, Miss Marrable, she meets her cousin Walter, an army Captain home on leave from India and soon realises that she has fallen in love with him. Mary’s relatives disapprove of the liaison. Captain Marrable’s father is a worthless rake who has illegally spent his son’s inheritance, leaving him penniless.

Gradually the opprobrium of the family drives the couple apart, and Walter departs to a distant relative’s estate to lick his wounds until he can return to his military life. Harry Gilmore, sensing that he may have another chance, renews his suit in earnest, and eventually persuades an indifferent Mary to accept his hand, despite her withering assertion that, were her cousin to ask for her hand again, she would drop the besotted Harry without a moment’s thought. Harry more interested in winning the prize than the prize herself agrees to these humiliating terms.

But fate has a surprise in store. Carry Brattle, the daughter of the local miller, is the other focus of the novel. She is a woman who – compared with Mary Lowther – has even fewer choices open to her. Carry is a prostitute; that is to say, what Trollope makes clear to us is that she has had sex with a man out of wedlock, is still unwed and is therefore regarded as a harlot. She is cast from the family home by her proud father, Jacob, yet Trollope’s depiction of the pathetic girl is never less than sympathetic.

The Vicar repeatedly tries to help her, particularly when she becomes involved as a valuable witness in a murder case, but inexorably, Carry is drawn towards the unforgiving gaze of the public eye. Will the miller stand by his daughter, or let convention, pride and shame get in the way of his true feelings for her?

A comic subplot involves the pompous Marquis of Trowbridge. He decides to punish what he perceives as Mr Fenwick’s insolence towards him by building a Methodist Chapel a few hundred yards from his front gate. Mr Fenwick, who usually relishes a good quarrel, fails to prevent the chapel’s construction, which threatens in turn the harmony of the sleepy town of Bullhampton. But a relative of Mrs Fenwick – Mr Quickenham QC – discovers that the Marquis has inadvertently built the chapel on glebe land…