The Dashwood family is introduced; Mr. and Mrs. Dashwood and their three daughters live at Norland Park, an estate in Sussex. Unfortunately, Mr. Dashwood's wife and daughters are left with very little when he dies and the estate goes to his son, John Dashwood. John and his wife Fanny (nee Ferrars) have a great deal of money, yet refuse to help his half-sisters and their mother.
Elinor, one of the Dashwood girls, is entirely sensible and prudent; her sister, Marianne, is very emotional and never moderate. Margaret, the youngest sister, is young and good-natured. Mrs. Dashwood and her daughters stay at Norland for a few months, mostly because of the promising friendship developing between Elinor and Edward Ferrars, Fanny's shy, but very kind, brother. Elinor likes Edward, but is not convinced her feelings are mutual; Fanny is especially displeased by their apparent regard, as Edward's mother wants him to marry very well.
A relative of Mrs. Dashwood's, Sir John Middleton, offers them a cottage at Barton Park in Devonshire; the family must accept, and are sad at leaving their home and having to separate Edward and Elinor. They find Barton Cottage and the countryside around it charming, and Sir John Middleton a very kind and obliging host. His wife, Lady Middleton, is cold and passionless; still, they accept frequent invitations to dinners and parties at Barton Park.
The Dashwoods meet Mrs. Jennings, Sir John's mother-in-law, a merry, somewhat vulgar older woman, and Colonel Brandon, a gentleman and a bachelor. The Colonel is soon taken with Marianne, but Marianne objects to Mrs. Jennings attempts to get them together, and to the "advanced" age (35) and serious demeanor of the Colonel.
Marianne falls and twists her ankle while walking; she is lucky enough to be found and carried home by a dashing man named Willoughby. Marianne and Willoughby have a similar romantic temperament, and Marianne is much pleased to find that Willoughby has a passion for art, poetry, and music. Willoughby and Marianne's attachment develops steadily, though Elinor believes that they should be more restrained in showing their regard publicly.
One pleasant day, the Middletons, the Dashwoods, and Willoughby are supposed to go on a picnic with the Colonel, but their plans are ditched when Colonel Brandon is forced to leave because of distressing news. Willoughby becomes an even more attentive guest at the cottage, spending a great deal more time there than Allenham with his aunt. Willoughby openly confesses his affections for Marianne and for all of them, and hopes they will always think of him as fondly as he does of them; this leaves Mrs. Dashwood and Elinor convinced that if Marianne and Willoughby are not engaged, they soon will be.
One morning, Mrs. Dashwood, Elinor, and Margaret leave the couple, hoping for a proposal; when they return, they find Marianne crying, and Willoughby saying that he must immediately go to London. Mrs. Dashwood and Elinor are completely unsettled by this hasty departure, and Elinor fears that they might have had a falling-out. Marianne is torn up by Willoughby's departure, and Elinor begins to question whether Willoughby's intentions were honorable. But, whether Willoughby and Marianne are engaged remains a mystery, as Marianne will not speak of it.
Edward comes to visit them at Barton, and is welcomed very warmly as their guest. It is soon apparent that Edward is unhappy, and doesn't show as much affection for Elinor; when they spot a ring he is wearing, with a lock of hair suspiciously similar to Elinor's, even Elinor is baffled. Edward finally forces himself to leave, still seeming distressed.
Sir John and Mrs. Jennings soon introduce Mrs. Jennings' other daughter, Mrs. Palmer, and her husband to the family. Mrs. Palmer says that people in town believe that Willoughby and Marianne will soon be married, which puzzles Elinor, as she knows of no such arrangements herself. Elinor and Marianne meet the Middletons' new guests, the Miss Steeles, apparently cousins; they find Miss Steele to be nothing remarkable, while Lucy is very pretty but not much better company. However, the Miss Steeles instantly gain Lady Middleton's admiration by paying endless attention to her obnoxious children.
Elinor, unfortunately, becomes the preferred companion of Lucy. Lucy inquires of Mrs. Ferrars, which prompts Elinor to ask about her acquaintance with the Ferrars family; Lucy then reveals that she is secretly engaged to Edward. It turns out that Edward and Lucy knew each other while Edward studied with Lucy's uncle, Mr. Pratt, and have been engaged for some years. Although Elinor is first angry about Edward's secrecy, she soon sees that marrying Lucy will be punishment enough, as she is unpolished, manipulative, and jealous of Edward's high regard for Elinor.
The Miss Steeles end up staying at Barton Park for two months. Mrs. Jennings invites Marianne and Elinor to spend the winter with her in London. Marianne is determined to go to see Willoughby, and Elinor decides she must go too, because Marianne needs Elinor's polite guidance. They accept the invitation, and leave in January. Once in town, they find Mrs. Jennings' house comfortable, and their company less than ideal; still, they try their best to enjoy it all.
Marianne anxiously awaits Willoughby's arrival, while Elinor finds her greatest enjoyment in Colonel Brandon's daily visits. Elinor is much disturbed when Colonel Brandon tells her that the engagement between Marianne and Willoughby is widely known throughout town. At a party, Elinor and Marianne see Willoughby; Marianne approaches him, although he avoids Marianne, and his behavior is insulting.
Marianne angrily writes Willoughby, and receives a reply in which he denies having loved Marianne, and says he hopes he didn't lead her on. Marianne is deeply grieved at being deceived and dumped so coldly; Elinor feels only anger at Willoughby's unpardonable behavior. Marianne then reveals that she and Willoughby were never engaged, and Elinor observes that Marianne should have been more prudent in her affections. Apparently, Willoughby is to marry the wealthy Lady Grey due to his constant need for money.
Colonel Brandon calls after hearing the news, and offers up his knowledge of Willoughby's character to Elinor. Colonel Brandon was once in love with a ward to his family, Eliza, who became a fallen woman and had an illegitimate daughter. Colonel Brandon placed the daughter, Miss Williams, in care after her mother's death. The Colonel learned on the day of the Delaford picnic that she had become pregnant, and was abandoned by Willoughby. Elinor is shocked, though the Colonel sincerely hopes that this will help Marianne feel better about losing Willoughby, since he was not of solid character.
The story convinces Marianne of Willoughby's guilt, though it does not ease her mind. Out of sympathy, Marianne also stops avoiding the Colonel's company and becomes more civil to him. Willoughby is soon married, which Marianne is grieved to hear; then, again unfortunately, the Miss Steeles come to stay with the Middletons.
John and Fanny Dashwood arrive, and are introduced to Mrs. Jennings, and to Sir John and Lady Middleton, deeming them worthy company. John reveals to Elinor that Edward is soon to be married to Miss Morton, an orphan with a great deal of money left to her, as per the plans of his mother. At a dinner party given by John and Fanny for their new acquaintance, Mrs. Ferrars is present, along with the entire Barton party. Mrs. Ferrars turns out to be sallow, unpleasant, and uncivil; she slights Elinor, which hurts Marianne deeply, as she is Edward's mother.
The Miss Steeles are invited to stay with John and Fanny. But, Mrs. Jennings soon informs them that Miss Steele told Fanny of Lucy and Edward's engagement, and that the Ferrars family threw the Steele girls out in a rage. Marianne is much grieved to hear of the engagement, and cannot believe that Elinor has also kept her knowledge of it a secret for so long. Edward is to be disinherited if he chooses to marry Lucy; unfortunately, Edward is too honorable to reject Lucy, even if he no longer loves her. Financial obstacles to their marriage remain; he must find a position in the church that pays enough to allow them to marry. Much to Elinor's chagrin, the Colonel, although he barely knows Edward, generously offers the small parish at Delaford to him. Elinor is to convey the offer to Edward, though she regrets that it might help the marriage.
Edward is surprised at the generous offer, since he hardly knows the Colonel. Edward decides to accept the position; they say goodbye, as Elinor is to leave town soon. Much to Elinor's surprise, Robert Ferrars, Edward's selfish, vain, and rather dim brother, is now to marry Miss Morton; he has also received Edward's inheritance and money, and doesn't care about Edward's grim situation.
It is April, and the Dashwood girls, the Palmers, and Mrs. Jennings, and Colonel Brandon set out for Cleveland, the Palmer's estate. Marianne is still feeling grief over Willoughby; she soon becomes ill after her walks in the rain, and gets a serious fever. The Palmers leave with her child; Mrs. Jennings, though, helps Elinor nurse Marianne, and insists that Colonel Brandon stay, since he is anxious about Marianne's health. Colonel Brandon soon sets off to get Mrs. Dashwood from Barton when Marianne's illness worsens. At last, Marianne's state improves, right in time for her mother and the Colonel's arrival; but Willoughby makes an unexpected visit.
Elinor is horrified at seeing him; he has come to inquire after Marianne's health and to explain his past actions. Willoughby says he led Marianne on at first out of vanity; he finally began to love her as well, and would have proposed to her, if not for the money.
By saying that he also has no regard for his wife, and still loves Marianne, he attempts to gain Elinor's compassion; Elinor's opinion of him is somewhat improved in being assured of his regard for Marianne. Elinor cannot think him a total blackguard since he has been punished for his mistakes, and tells him so; Willoughby leaves with this assurance, lamenting that Marianne is lost to him forever.
Mrs. Dashwood finally arrives, and Elinor assures her that Marianne is out of danger; both Mrs. Dashwood and the Colonel are relieved. Mrs. Dashwood tells Elinor that the Colonel had confessed his love for Marianne during the journey from Barton; Mrs. Dashwood wishes the Colonel and Marianne to be married. Elinor wishes the Colonel well in securing Marianne's affections, but is more pessimistic regarding Marianne's ability to accept the Colonel after disliking him for so long.
Marianne makes a quick recovery, thanking Colonel Brandon for his help and acting friendly toward him. Marianne finally seems calm and happy as they leave for Barton, which Elinor believes to signal Marianne's recovery from Willoughby. She is also far more mature, keeping herself busy and refusing to let herself languish in her grief.
When Marianne decides to talk about Willoughby, Elinor takes the opportunity to tell her what Willoughby had said at Cleveland, and Marianne takes this very well. Marianne also laments her selfishness toward Elinor, and her lack of civility toward most of their acquaintance. Marianne finally says that she could not have been happy with Willoughby, after hearing of his cruelty toward Miss Williams, and no longer regrets him.
The family is stunned when one of their servants returns with news that Edward is married to Lucy, as he just saw them in the village. Elinor knows now that Edward is lost to her forever. Mrs. Dashwood sees how upset Elinor is, and realizes that Elinor felt more for Edward than she ever revealed. One afternoon, Elinor is convinced that the Colonel has arrived at the cottage, but is surprised to find that it is Edward instead. Their meeting is awkward at best; he soon informs them that it is his brother who has been married to Lucy, and not him. Elinor immediately runs from the room, crying out of joy; Edward then senses Elinor's regard for him, and proposes to her that afternoon. Elinor accepts and he gains Mrs. Dashwood's consent to the match.
Edward admits that any regard he had for Lucy was formed out of idleness and lack of knowledge; he came to regret the engagement soon after it was formed. After leaving London, Edward received a letter from Lucy saying that she had married his brother Robert, and has not seen her since; thus, he was honorably relieved of the engagement. After receiving the letter, he set out for Barton immediately to see Elinor. Edward will still accept the position at Delaford, although he and Elinor again will not have enough money to live on comfortably. The Colonel visits Barton, and he and Edward become good friends.
Edward then becomes reconciled with his family, although he does not regain his inheritance from Robert. His mother even gives her consent for his marriage to Elinor, however much she is displeased by it; she gives them ten thousand pounds, the interest of which will allow them to live comfortably. Edward and Elinor are married at Barton that fall.
Mrs. Dashwood and her two remaining daughters spend most of their time at Delaford, both to be near Elinor, and out of the hope that Marianne might accept the Colonel. In the two years that have passed, Marianne has become more mature and more grounded; and she does finally change her mind about the Colonel, and accepts his offer of marriage. The Colonel becomes far more cheerful, and soon Marianne grows to love him as much as she ever loved Willoughby. Mrs. Dashwood remains at Barton with Margaret, now fifteen, much to the delight of Sir John, who retains their company. And Elinor and Marianne both live together at Delaford, and remain good friends with each other and each other's husbands.