The narrator claims that it is difficult to write introductory chapters. They are not ordered in a particular manner—any of them could grace the beginning of any chapter. Their purpose is simply to whet the critic's appetite.
Western and Sophia—who is still confined to her room—argue about Blifil. A messenger arrives from Lord Fellamar, who intends to pay his respects to Sophia that afternoon. Western answers that Sophia is already "disposed of." The messenger asks whether Western knows what kind of man he is declining. Western rudely retort that he hates all lords and begins to caper angrily about the room. Sophia joins in her father's rancor by stomping her foot on the floor and running screaming from her room. Once Fellamar's messenger has departed, Western heads straight for Sophia's room, where they weep together and express their love for each other. Sophia says that she promises not to marry at all—she will devote herself to her father. This refuels his anger.
The narrator confides in the reader that Western "really doated on his Daughter, and to give her any Kind of Pleasure was the highest Satisfaction of his Life." Black George carries up a pullet with eggs for Sophia's dinner. Although Sophia has been refusing food, Black George manages to entice her with the pullet, which is her favorite dish. She finds a letter from Tom inside its belly. The letter labors the point that Tom only wishes to see Sophia happy. While she reads the letter, Sophia hears a fracas downstairs between her father and her Aunt Western, who has just arrived in London.
Mrs. Western asks for her niece. When Squire Western reports that he has locked the wayward Sophia in her room, Mrs. Western reminds him of his promise not to take such drastic actions against his daughter's disobedience. She stresses the ideal of female liberty, and the narrator compares her to Thalestris, that Amazonian champion of women. Eventually Squire Western tosses down the key and Mrs. Western departs to find Sophia. No sooner has she left than her brother damns her and invites Parson Supple for a drink. Squire Western allows Mrs. Western to take Sophia to her own lodging. Mrs. Western begs her brother not to see Mrs. Fitzpatrick if she seeks him out.
Black George delivers a letter to Tom from Sophia. She tells Tom that she is with her Aunt Western and has promised not to write any further to Tom. She does give her word, however, that she will marry no other man. Tom is torn by happiness and grief. Tom spends three hours reading and kissing the epistle, after which he joins Mrs. Miller, Betsey, and Partridge at the playhouse to watch a performance of Hamlet. Partridge becomes fully immersed in the play and trembles at the ghost of Hamlet's father—whom he believes to be a real ghoul. He shouts out to Hamlet when the latter picks up the skull of Yorrick, and amuses all the spectators around him with his running commentary on the play. After the performance, Mrs. Fitzpatrick approaches Jones and invites him to meet with her the following afternoon.
The narrator considers all the characters in the novel as children. He harbors an "extraordinary Tenderness" for Sophia. Soon after Mr. Western departed for London, he sent a note to Blifil encouraging the lad to come to London as soon as possible to be married to Sophia. Blifil's motive for marrying Sophia has become pure hatred. Since Sophia ran away from home, Allworthy has suspected Sophia's dislike for Blifil. Blifil and Thwackum tried to convince Allworthy that Blifil should still pursue the young lady. Allworthy's tenderness eventually conquered his prudence and he agreed to accompany Blifil to London. Allworthy and Blifil arrive in London while Jones is watching Hamlet. Western insists on taking Blifil to Mrs. Western's residence immediately.
Mrs. Western is reading Sophia a lecture on the prudence and politics of marriage when Mr. Western barges in with Blifil. Mrs. Western chastises him for not following the principles of a decorous entrance and sends Sophia—who she claims has been shaken by the event—to her bedroom. Blifil blubbers and blunders in fear. Mrs. Western says that he may leave a message for Sophia. Blifil leaves, less pleased with the meeting than Western. Western puts their failure down to Mrs. Western's mood, but Blifil suspects something more lurks beneath the surface.
Fellamar is still passionately in love with Sophia and, inspired by Lady Bellaston, has commissioned Captain Egglane to force Tom onto a ship. Mrs. Western sent a greeting card to Lady Bellaston on her arrival in London. Lady Bellaston, delighted to have a female partner in crime, runs to Mrs. Western with her news about Lord Fellamar. Mrs. Western dubs Blifil a "hideous kind of Fellow" like "all country Gentlemen." Lady Bellaston now gives Mrs. Western the marriage proposal she received from Tom. She says she hopes the letter will change Sophia's mind. It was directly after this conference that Western and Blifil made their appearance, which explains Mrs. Western's icy behavior to the latter.
Jones meets with Mrs. Fitzpatrick, who suggests that Jones should try to get access to Sophia by flirting with Mrs. Western. She reminds him that this is what Mr. Fitzpatrick did in order to court her, and it worked. Jones politely declines the suggestion, infuriating Mrs. Fitzpatrick. Jones attempts to assuage Mrs. Fitzpatrick, who now takes a fancy to Jones. Out of vanity she believes herself to be one of the finest ladies in the world. As Jones leaves, Mrs. Fitzpatrick gazes at him seductively and invites him to visit her the following day. Jones's thoughts, however, tend only toward Sophia and he resolves not to call on Mrs. Fitzpatrick.
Mr. Fitzpatrick, who has tracked his wife to London, arrives at her doorstep as Jones is departing. Jones recognizes him from the inn at Upton and greets him amicably, but Fitzpatrick punches him and draws his sword out. Jones knows nothing about fencing but manages to retaliate and plunges the sword into Fitzpatrick. Jones, calling for assistance for Fitzpatrick, is apprehended by a gang of men employed by Lord Fellamar. Jones lands up in jail after a trial. Partridge visits Jones at the prison with news of Fitzpatrick's death. Sophia sends Tom a letter saying that she has seen his proposal letter to Lady Bellaston and wishes to have nothing more to do with him.
Book XVI brings the novel to its climax: it builds steadily through the collusion of Mrs. Western, Lady Bellaston, and Mrs. Fitzpatrick—each of whom harbors her own reason for wanting to contrive a marriage between Sophia and Lord Fellamar—and culminates in the duel between Tom Jones and Fitzpatrick. Fellamar's courtly status as a "lord" and the fact that he is one of the richest men in England appeals to Mrs. Western, who now calls Blifil a "vile" countryman. Her attitude contrasts with that of Squire Western, which sets the two fighting for control of Sophia in Chapter IV. Squire Western grows in the reader's estimation in this chapter since the narrator admits in Chapter III that Western "really doated on his Daughter, and to give her any Kind of Pleasure was the highest Satisfaction of his Life." Although Lady Bellaston has lost all chances with Tom, out of spite she wishes to keep him apart from Sophia. Mrs. Fitzpatrick is still trying to restore herself to the favor of her aunt and uncle by procuring a good marriage for Sophia.
Fielding's philosophy about his prefacing chapters, expressed in Chapter I, contrasts with the finely designed linear narrative of Book XVI. By claiming that the prefacing chapters have been randomly placed and deserve no particular order, Fielding sets up a "timeless" axis as opposed to his "time-dependent" axis. His introductory chapters and intrusive philosophical musings belong to the former axis, while his highly contrived narrative belongs to the latter category.