Sophia is at church and is touched by Molly's beauty. Sophia later calls on Black George to tell him she would like to hire Molly as her maid servant. Black George is secretly shocked that Sophia has not noticed that Molly is pregnant. He heads home for advice from his wife, but the family is in an uproar over what happened at church, when the women assaulted Molly with "Dirt and Rubbish." In retaliation, Molly knocked out the leader of the pack and cleared herself a path using a skull and thighbone from the graveyard as her weapons. The narrator tells the story in an ironic Virgilian style, listing the names of the men and women who fell victim to Molly. Goody Brown is the only woman to fight back. She attacks Molly and tears out her hair. The narrator observes that since women never fail to aim for each other's breasts when fighting, Goody Brown, who is flat-chested, has the upper hand. Tom's arrival quells the fight.
Tom covers Molly with his own clothes and gives orders for Molly to be transported home. Tom departs with Square and Blifil after stealing a quick kiss from Molly. Back in the Seagrim household, Molly is chastised by her sisters. Mrs. Seagrim calls Molly a whore, and Molly reminds her mother that she was also pregnant with her first child before she was married. Black George tells his family about Sophia's offer. Molly does not want to wash dishes for Sophia, and after Molly slips her mother some money, Mrs. Seagrim agrees that Molly is too good to be a maid. Mrs. Seagrim accuses her husband of being a villain who causes trouble for the family by fighting everyone, and it is decided that Mrs. Seagrim will take the job herself.
The following morning, Tom goes hunting with Squire Western and returns to dine with him, Sophia, and Parson Supple the parish curate. Sophia radiates with charm and beauty, finally conquering Tom. Parson Supple is known for his reticence while eating, but after dinner he makes amusing conversation. He happens to drop the news that Molly Seagrim is pregnant and that her father is swearing to send her to Bridewell. Tom excuses himself from the table, which leads Western to exclaim that Tom must be the father of the child. Now he says he understands why Tom pleaded so heartily on Black George's behalf. Parson Supple takes Tom's side, and Western calls Allworthy a "whoremaster," and implies that he was a lover-boy while at university. Parson Supple retorts that Allworthy never attended university. Sophia, having noticed Tom blush during Parson Supple's story, begins to suspect that her father is right. After the guests have left, Western wants Sophia to play the harpsichord for him, but she complains of a raging headache.
Tom returns home on foot to find Molly about to be whisked off to Bridewell. He embraces her in front of everyone and swears he will protect her. Tom speaks to Allworthy and confesses that he is the father of the child. Allworthy sends Molly home and gives Tom a lecture on chastity. The narrator says there is no point in his transcribing this, since we have already witnessed Allworthy's speech to Jenny Jones, and most of what applies to women applies likewise to men. Allworthy disapproves of Tom's behavior but appreciates Tom's honesty. Blifil relates the story to Thwackum, who is enraged that Tom is too old for a whipping. Thwackum conceives of a plan to corrupt Allworthy's opinion of Tom. Square suggests to Allworthy that Tom has only been friendly to Black George in order to win over Molly. The seeds of suspicion are laid in Allworthy's mind.
Sophia does not sleep well and her maid, Mrs. Honour, finds her awake and fully dressed the next morning. Mrs. Honour imparts to Sophia that Tom is indeed the father of Molly's child. Sophia does not want to hear about it, and sends Mrs. Honour to see whether Sophia has to attend to her father at breakfast. The narrator reminds us of Sophia's burgeoning love for Tom, which has now overwhelmed her. Sophia decides that the only cure for her lovesickness is to avoid Tom by making a visit to her aunt. However, an accident will prevent her from leaving.
Mr. Western insists that Sophia join him on a hunting expedition, even though she has no love for violent sports. On the second day, Sophia's horse throws her off and Tom gallops in and catches her, breaking his left arm in the process. Western is elated that his daughter has been rescued and Sophia secretly cherishes Tom's bravery. The narrator delves into examples of philosophers who believe men to outshine women in bravery, and women who love courage in men. Whatever the case, the accident brings Tom and Sophia closer together.
A surgeon bleeds Sophia and performs surgery on Tom's arm. Mrs. Honour prattles to Sophia about Tom's magnamity and good looks, and accuses Sophia of being in love with Tom. Mrs. Honour also tells Sophia that she saw Tom passionately kissing Sophia's muff, which he found lying on a chair. Moreover, when Sophia was playing the harpsichord one day, Tom observed that he could not speak while Sophia was playing. Sophia hushes Honour, protesting that she does not want to hear such talk, but when Honour tells Sophia that Tom once called her a "goddess" Sophia listens intently.
Book IV initiates the love affair between Tom and Sophia. Fielding undercuts the romantic notion of love, however, with the manner in which he describes Sophia, and with the introduction of Molly Seagrim. After rallying his poetic powers in Chapter I for a theatrical presentation of his heroine, the narrator remains elusive in his description of Sophia in Chapter II. It may seem strange that a writer as concerned with detail as Fielding would avoid providing a full picture of his heroine, but his awareness of literary stereotypes of beauty encourage him to treat the topic of beauty with some irony and humor. Reminding the reader of the effort it takes to create a Sophia, the narrator promises to "endeavour with our utmost Skill to describe this Paragon, though we are sensible that our highest Abilities are very inadequate to the Task." Fielding's false modesty parodies previous writing in which heroines are described as walking perfections.
Fielding's vision of the "novel" begins to truly emerge in Book IV. Fielding's narrative certainly takes precedence over florid descriptions and, as mentioned above, he even parodies classical writers' passion for extravagant language. Fielding's writing is pithy and pointed, and he packs each scene with narrative detail. He substitutes flowery, poetic language with a hardened, ironic sort of fictional reporting, and his main interest is to distinguish his characters from one another. Fielding also alludes, however, to people whom he actually knew in England at the time he was writing the novel, thereby grounding the novel in a real historical context. Fielding constantly uses hyperbole to achieve a comic effect. For example, in mock pomp he summons a muse in Chapter VIII to help describe the fight that breaks out between Molly and the parish women at church. With the muse's help, Fielding casts the scene as a widespread war, sprinkling the description with military jargon. The humor of the scene comes from the contrast between Fielding's overflowing, grandiose prose and the grotesque image of two topless women fighting in front of their church.