The story, set in the countryside of England, revolves around the life of Emma Woodhouse, her father, Mr. Knightley and other residents of Highbury. Emma who takes care of her hypochondriac father, and has decided not to get married herself, likes to meddle in peoples' love lives. One such meddling breaks her friend Harriet's heart. Emma, then, resolves not to meddle ever again in anything that does not concern her. Parellelly, the book describes the woes and joys of the families at Randalls, the vicarage, Donwells and the Main Street.
Emma is considered to be Jane Austen's most serious book (though I think Northanger Abbey must earn that title).