Emma Woodhouse, “handsome, clever, and rich” is the most eligible young woman in the restricted social scene of Highbury, a large village in Surrey, but is determined not to marry, though she delights in match-making. Her former governess has just married Mr Weston, a prosperous man who has settled in a large house in the area. Emma takes up Harriet Smith, a pretty girl who has been placed in a local school by unknown parents, and tries to marry her off to the vicar, Mr Elton, who co-operates because he thinks he is wooing Emma. When the truth is revealed all three are mortified, and Mr Elton goes off to find another wife. Mr Knightley, the great landowner of the area, disapproves of Emma's continuing attempts to prevent Harriet from marrying Robert Martin, a farmer's son. Frank Churchill, Mr Weston's son by his first marriage, who has been adopted by the first wife's snobbish and domineering relations, appears on the scene coincidentally with Jane Fairfax, the niece of Miss Bates, the village chatterbox. He flirts mildly with Emma. The death of the tyrannical Mrs Churchill reveals that Frank has been doing this in order to disguise his engagement to Jane Fairfax. Mr Knightley's protection of Harriet against the malice of Mr Elton leads her to think that he is in love with her, and this makes Emma realise that she cannot bear the thought of Mr Knightley marrying anyone but herself. Eventually Mr Knightley, impressed by Emma's remorse at her own failings, proposes to her, and they are married, while Harriet marries Robert Martin.
The characters in this story include the valetudinarian Mr Woodhouse, Emma's father, whose comforts and idiosyncrasies always have to be accommodated; the sensible and affectionate Mrs Weston, and John Knightley, Mr Knightley's younger brother, a London lawyer; and Emma's older sister Isabella, married to John Knightley.
In describing Mr Elton as “so well understanding the gradations of rank below him and . . . so blind to what rose above”, the author hits on one of the central themes, if not the central theme: that of which movements up and down the social scale are or are not acceptable. The scale is carefully graded, from Mr Woodhouse at the top down to James the coachman's daughter who has been found a place as a maid with the Weston household (some gypsies who appear being completely outside this social structure). Mr Elton, the clergyman who aspires to the hand of Emma, is horrified at the idea of marrying the (presumed) bastard daughter of an unknown father, but he himself marries a vulgar woman who mistakenly aspires to the social leadership of the small community. Harriet Smith, having no special accomplishments, is lucky in attracting the attention of a prosperous farmer's son.