Henry Dashwood lived at Norland Park in Sussex, England, a property owned by his wealthy uncle. Henry had three daughters by his current wife and one son from a prior marriage. When his uncle died, Norland was left to Henry's son John and John's own son. This left Henry's three daughters without much of a fortune, and when he died, he asked John to look after his half-sisters. John, in response, plans to give his sisters 3000 pounds each, but his wife Fanny quickly persuades him not to do this, so that their own son will have that money. Henry's widow, Mrs. Dashwood, and her three daughters (the rational and self-controlled Elinor, the sensitive Marianne, and the young Margaret) stay at Norland for several months after Henry's death. Mrs. Dashwood despises Fanny, but Elinor becomes close with Fanny's brother, Edward Ferrars. Mrs. Dashwood and Marianne think he and Elinor will marry. A relative of Mrs. Dashwood, Sir John Middleton, writes to her and offers her a place to live on his property, Barton Park. Mrs. Dashwood accepts the offer, and moves to a cottage on Sir John's property with her daughters. The Dashwoods meet Sir John and his wife, Lady Middleton, often attending dinners and balls at their home. They also meet Lady Middleton's mother, a kind but gossipy old woman named Mrs. Jennings, who enjoys predicting and encouraging budding romances. Another frequent guest at the Middletons' home is Colonel Brandon, a friend of Sir John and a 35 year-old bachelor. It quickly becomes apparent that Brandon loves Marianne, but Marianne thinks the idea of marrying a man so old and as lacking in taste as she thinks Brandon to be is ridiculous.

One day, The Dashwood sisters go out for a walk in the country. When it begins to rain suddenly, they run back toward their cottage, but Marianne trips and falls. A gentleman who happens to be passing by picked her up and gallantly carries her home. He introduces himself as Willoughby. Soon after, the Dashwoods see Willoughby again at dinner at Barton Park. Sir John tells Marianne that Willoughby is "very well worth catching," and she begins to grow fond of him. Willoughby often visits the Dashwood cottage and spends much time with Marianne. They share many of the same opinions and tastes in art, music, and literature. Mrs. Dashwood guesses that they might become engaged. Marianne and Willoughby grow closer and closer, as the Dashwoods continue to attend numerous social events at Barton Park. Margaret sees Marianne give Willoughby a lock of her hair, and assumes that they are engaged. One evening at Barton Park, Mrs. Jennings asks Elinor if she had any man whom she was fond of, and Margaret lets slip that Elinor is taken by someone whose name began with an F. The next day, a large group assembles at Barton Park to make an expedition to Colonel Brandon's brother-in-law's property. However, Brandon receives a letter and suddenly has to leave for London, cancelling the planned trip. Everyone decides to pass the day by driving around the country, and Willoughby and Marianne go off in one carriage to his aunt's property, Allenham, which he is likely to inherit, and they survey it together. Over the next few days, Willoughby continues to behave as though he is in love with Marianne.