One evening that summer, Rose sits down to play the piano for her aunt, when suddenly her aunt, noticing that something is wrong with Rose, asks her what is the matter. Rose replies that, although for some time she has been trying to hide it, she does not feel well—she believes that she is growing ill.
Dickens does not elaborate on what might be the cause of Rose's illness, nor does he explain why Rose suddenly feels better. What's more important, in this scene, is the destabilizing effect Rose's illness has on the Maylie family.
Oliver asks Mrs. Maylie, when Rose has been safely placed in bed, whether Rose will get better, but Mrs. Maylie fears instead that Rose will only grow sicker, and eventually pass away. Oliver is surprised by Mrs. Maylie's negative outlook. The next morning, however, Mrs. Maylie seems poised to help her niece, and to fight off melancholy. She dispatches Oliver to Lorsborne's, with a note informing him of Rose's fever. Oliver notices another letter for a man named Harry Maylie, but when he inquires of Mrs. Maylie whether he ought to deliver that one, too, she says no, that it should wait for the next day.
The novel has so far moved along without a romantic interest, but now Dickens supplies one (perhaps to satisfy those reading the novel in serialized form). Harry and Rose's romance does not occupy too much of the novel's remaining pages, but it contains enough interest to create a genuine romantic spark in a book that otherwise charts the ups and downs of the life of a ten-year-old—a boy too young for this kind of romantic attachment.
Oliver runs all the way to the market, four miles off, with the letter for Lorsborne (it will be taken from the market to Lorsborne by coach). While running back home from dropping off the letter, however, Oliver nearly crashes into a strange gentleman, who curses at Oliver in a manner far outstripping the small, accidental offense Oliver caused; the strange man says, among other things, "He'd start up from a marble coffin, to come in my way!" Oliver is perturbed by this man's behavior, but continues running along.
Another coincidence, although this one is later "explained" by the fact that Monks knew Oliver was being rehabilitated in the small farmhouse outside Chertsey. Nevertheless, Monks does not introduce himself to Oliver, and of course Oliver has never seen Monks before. It should be noted that Oliver resembles his mother, meaning he does not look at all—it can be inferred—like his half-brother, Monks, who shares only a father with Oliver.
When Oliver returns home, Rose's fever has grown worse—Lorsborne, who arrives later, fears that Rose might not survive it. After a few days, in which neither Oliver nor Mrs. Maylie sleep hardly at all, Lorsborne emerges from the sick room, after another visit, to declare that, finally and against all hope, Rose appears to be on the mend. Mrs. Maylie can barely believe the news—she feared that her niece was lost. And Oliver is overjoyed to hear Lorsborne's new prognosis.
The dramatic compression in this chapter is notable. At first, Rose is well; then she is sick; then she is violently sick, almost on the verge of death; and when it appears there is no longer hope, she recovers quickly. Again, it is not clear why Dickens inserted this small character arc in the novel, over than to emphasize the importance of Rose's goodwill on the structure of the Maylie family.