Elinor and Marianne leave London, after receiving invitations to visit their brother again, and from Lucy to visit her in Delaford. The last invitation would always be declined, because of the difficulty for Elinor, to see Edward married to another woman. Marianne, even though anxious to leave London, in the end cries at their departure, whereas Elinor is happy to be away from the people there.

They travel two days to Cleveland, the home of Mr. and Mrs. Palmer. Marianne upon their arrival decides to spend as much time out exploring the grounds as she can. She is not even put off by wet weather, only staying inside during the rainiest parts of the day.

The ladies, Charlotte Palmer, Mrs. Jennings, Elinor, and Marianne are joined two days later by Mr. Palmer and Colonel Brandon. Mr. Palmer, who Elinor does not know well, turns out to be a more pleasant man than she had expected him to be. Colonel Brandon is, as always, attentive to Elinor and seeks her out for pleasant conversation. She, unlike Mrs. Jennings, knows his true desire is to date Marianne and not her.

Marianne becomes sick from walking in the cold and staying in her wet shoes and stockings. She has a cold with a fever and body aches, which everyone gives her different remedies to cure her ailment. A good night's rest is thought to be just the thing to cure her.

A good night's sleep does not cure Marianne, instead she steadily becomes worse to the point the local apothecary, Mr. Harris, is called to the house. He announces that Marianne has an infection and needs to take medicine, but he thinks she will be well in a few days.

Mrs. Palmer fearing for her infant son's well-being, takes him to a relative's home to stay while Marianne is ill. Mr. Palmer leaves a few days later to join her, but Colonel Brandon is encouraged by Mrs. Jennings to stay.

Meanwhile, Marianne is becoming more ill by the day, but Elinor still thinks she will regain her health soon. It is not until the night, when Marianne becomes delirious, does she send for Mr. Harris and asks Colonel Brandon to bring their mother. Elinor is afraid she has waited too long to call for her mother and Marianne might be dead before she arrives.

Mr. Harris tries two more medicines, between that night and the next day, before Marianne starts to show signs of recovery. On his next visit Mr. Harris declares Marianne out of danger and recovering.

Elinor when she hears a carriage arriving at the house, even though it is two hours early, is convinced her mother is there. She rushes to greet her only to be disappointed, because the visitor is Willoughby.

Willoughby has heard from Sir John about Marianne's illness, he decides she cannot die without knowing he is ashamed of how he treated her and the reasons why he ended their relationship.

He has no choice, but to tell all of this to Elinor, since Marianne is too ill to receive visitors. He tells Elinor he didn't want to have a romantic relationship with Marianne. He was going to inherit from his aunt, Mrs. Smith, but she was told about his illegitimate child. She was shocked by the news and demanded he marry the child's mother; he refused, so Mrs. Smith disinherited him.

He by this time had fallen for Marianne, but he had to end it because he had no money, so he told her he had to go to London on business. It was a lie, he instead went to London and met Miss Grey, whose fortune would restore him financially.

He had received Marianne's notes, but he could not see her. The night he saw them at the party, Miss Grey also saw Marianne and was very jealous. He tells Elinor it is his wife who wrote the last letter to Marianne and who forced him to return the lock of hair and the letters. He doesn't love Miss Grey and is miserable with her. He wants Elinor to tell Marianne he is sorry for the heartbreak he has caused and to let her know how miserable he is. He asks for Marianne's forgiveness, which Elinor tells him she has already given him.

Not long after Willoughby leaves does Mrs. Dashwood and Colonel Brandon arrive at the house. Elinor rushes to tell her mother the good news of Marianne's recovery. They are all overcome with joy and Mrs. Dashwood is soon reunited with her ailing daughter.

Elinor, as she tries to fall asleep, can think of nothing but Willoughby or "poor Willoughby", as she thinks of him now. She does not know how she will keep her promise to tell her sister about his visit.

Mrs. Dashwood later confides to Elinor the colonel confessed his love of Marianne to her, during the carriage ride to Cleveland. Mrs. Dashwood is already planning on the two of them being married and the possibility of her, Elinor, and Margaret moving to Delaford to be near them. This thought fills Elinor with dread, because Edward and Lucy will also be living at Delaford. Her mother is also thinking of how Colonel Brandon will be able to support her, in her advancing years.

Marianne is afflicted with an illness which leaves her close to death. This brings Willoughby to the Palmer's home, Cleveland, to explain his actions to her, so she will not die hating him, but he instead has to explain himself to Elinor. Marianne's illness also prompts Colonel Brandon to confess his love of her to Mrs. Dashwood. This gives Mrs. Dashwood the hope of marrying her daughter to a man with the means to support the whole family. These chapters bring sorrow, hope, and change to the characters of the book.