Northanger Abbey follows seventeen-year-old Gothic novel aficionado Catherine Morland and family friends Mr. and Mrs. Allen as they visit Bath. It is Catherine's first visit there. She meets new friends, such as Isabella Thorpe, and goes to balls. Catherine finds herself pursued by Isabella's brother, the rough-mannered, slovenly John Thorpe, and by her real love interest, Henry Tilney. She also becomes friends with Eleanor Tilney, Henry's younger sister. Henry captivates her with his view on novels and his knowledge of history and the world. General Tilney (Henry and Eleanor's father) invites Catherine to visit their estate, Northanger Abbey, which, from her reading of Ann Radcliffe's Gothic novel The Mysteries of Udolpho, she expects to be dark, ancient and full of Gothic horrors and fantastical mystery.

The story follows the main character Elizabeth Bennet as she deals with issues of manners, upbringing, morality, education, and marriage in the society of the landed gentry of early 19th-century England. Elizabeth is the second of five daughters of a country gentleman living near the fictional town of Meryton in Hertfordshire, near London.