Tom stands outside Dorlcote Mill. Maggie has been gone for five days, and Bob Jakin has reported seeing her with Stephen at Mudport. Maggie arrives at the mill, looking worn and tired from her journey from York and the headache that kept her in bed there for over a day. Maggie approaches Tom to tell him everything, but Tom, looking at her face, knows that the worst has happened—his sister has returned unmarried and disgraced. He rejects her, "I wash my hands of you forever. You don't belong to me." He will not listen to Maggie's explanations. Maggie turns away to leave, and Mrs. Tulliver reaches out to her and offers to go with her. Tom gives his mother money, and Mrs. Tulliver gets her things.
Maggie takes them to Bob Jakin's. Bob takes them in with no questions, though he know has heard all the town rumors about Maggie and Stephen after he saw them at Mudport, and is perplexed at seeing Maggie now alone. Several days later, Bob comes into the sitting room where Maggie is and gives her to hold his new baby, who they have named after Maggie. Maggie asks Bob to go to Dr. Kenn's and ask him to come to Maggie while Mrs. Tulliver is out. Bob reports that Mrs. Kenn has just died and that he wouldn't like to approach Dr. Kenn so soon. Maggie agrees to wait several days. Bob finally gets the courage to ask Maggie if she has been wronged (by Stephen) in any way. Maggie, surprised, says no and smiles at Bob's vehement wish to "leather him till I couldn't see" in the event of Stephen's misconduct. Bob gets up with the baby but offers to leave Mumps the dog for company.
Soon all of St. Ogg's knows that Maggie has returned, without Stephen. If she had returned married, public opinion would have been sympathetic and welcoming. But, having returned unmarried, Maggie's conduct is seen in the worst light and even her very physical appearance is interpreted ungenerously. Stephen, however, is seen in a positive light—as having been under Maggie's spell, but now having got rid of her as soon as possible. The town knows of Stephen's letter, sent from Holland a week after Maggie's return, taking all the blame on himself, but the town interprets this as false but gallant on Stephen's part.
Maggie, meanwhile, takes little notice of the town gossip, being too occupied with anxiety about Stephen, Lucy, and Philip. Her "life stretched before her as one act of penitence."
Maggie has decided to eventually persuade Mrs. Tulliver to go back to live with Tom at the mill, while Maggie finds some way to earn a living. Mrs. Tulliver visits the Deanes' every day to check on Lucy, who has been feeble and bedridden since the news. Mrs. Tulliver can get no news of Philip. In desperate hopes of more news, Mrs. Tulliver visits Mrs. Glegg.
While Mrs. Tulliver visits Mrs. Glegg, Maggie leaves Bob's to walk to Dr. Kenn's. It is Maggie's first time out of doors, and she is met by nasty looks and insolent treatment. Maggie's pride is hurt, and it occurs to her for the first time that people may think she's done worse than just violate Lucy's confidence—they make think she's been compromised sexually.
Maggie reaches Dr. Kenn's and tells him everything. Dr. Kenn is receptive—he has read Stephen's letter and believes Maggie. He congratulates her on the "true prompting" of her instinct to return to her past and her friends. Dr. Kenn urges Maggie to find work in another town and offers to help. But Maggie explains that she has already written to excuse herself from her summer work, as she desires to stay in St. Ogg's. Dr. Kenn agrees to try to help her find work in St. Ogg's.
Mrs. Tulliver reports to Maggie the unexpected news that Mrs. Glegg is standing by Maggie. Mrs. Glegg apparently had gone to Tom to reprove him for rejecting his sister before knowing the whole truth: "If you were not to stand by your 'kin' as long as there was a shred of honour attributable to them, pray what were you to stand by?" Mrs. Glegg has been standing strong on Maggie's behalf against many others. Tom, at least, however, remains unmoved in his refusal of Maggie. Mrs. Glegg has offered to take in Maggie and not reproach her.
Mrs. Tulliver reports that Lucy has begun to sit up in bed and take notice of people, though there is still no word for Maggie of Philip. Mrs. Tulliver laments, for the first time, the turn of family luck for the worse, and Maggie sadly repents.
Maggie finally asks Dr. Kenn about Philip, but no one has any word of him, since Wakem refuses to answer questions about his son. Finally, though, Maggie receives a letter from Philip expressing his forgiveness and understanding and a promise to wait for her and not press his continuing love for her. He credits Maggie's conduct in leaving Stephen and his love for her with having brought him out of egoistic jealousy to a state of "caring for [her] joy and sorros more than for what is directly [his] own." Maggie collapses in tears upon reading the letter at the thought of Philip and Lucy's pain.
The first trial that Maggie must face upon returning to St. Ogg's is a meeting with Tom. We have seen Maggie be hard on herself for virtually the entire novel, but Tom here is harder on her. His method of argument is reminiscent of Stephen's. There is a proliferation of accusatory first-person and the effect is to sound egoistic: "I have had feelings to struggle with; but I conquered them. I have had a harder life than you have had: but I have found my comfort in doing my duty. But I will sanction no such character as yours: the world shall know that I feel the difference between right and wrong." (The emphasis here is Eliot's). Tom's strict adherence to justice and fairness is revealed in the end to include an underlying vein of self-righteousness. Even Mrs. Tulliver, who has always privileged Tom over Maggie, now feels his lack of compassion and makes up for it herself.
The inclusion of the final scene in Chapter I between Bob and Maggie also serves to underline Tom's cruelty. Far from pre-judging Maggie, Bob's only thought is that Maggie may have been somehow wronged. Tom's formal ejection of Maggie from the Tulliver household and family is mirrored in reverse by Bob's taking Maggie into his house and choosing to name his daughter after Maggie.
In Chapter II of Book Seventh, Eliot is quite specific that the women of St. Ogg's and, indeed, any community, are responsible for the hypocritical judgments of morality. Far from being an accurate assessment of personal morality, in the opening paragraphs these judgments are shown to rest upon egotistical impulses and extraneous details of social convention. Indeed, egoism seems to be the common evil of the end of The Mill on the Floss. Not only do Stephen and Tom suffer from egoism, but the malicious gossip of the town is also the result of egoism. We will hear in Chapter IV of Book Seventh that "Society," is an abstraction created by the "ladies of St. Ogg's which served to make their consciences perfectly easy in doing what satisfied their own egoism." In contrast, Philip's letter explicitly outlines his recent shift from egoism to sympathy that has allowed him to think of Maggie and forgive her: "The new life I have found in caring for your joy and sorrow more than for what is directly my own, has transformed the spirit of rebellious murmuring into willing endurance which is the birth of strong sympathy."
Besides Philip, Bob Jakin, and Mrs. Tulliver, characters who counteract the egoism of the town ladies include Dr. Kenn and Mrs. Glegg. Dr. Kenn is a singular model of morality in The Mill on the Floss. His ethics and standards are put forth as the measure against Maggie is to be harshly judged, yet, in the end, vindicated in the novel. The support of Mrs. Glegg seems somewhat surprising in view of her contrary personal character, yet it is not at all surprising in relation to her strict code of family behavior. In this depiction of Mrs. Glegg, Eliot favorably contrasts the Dodson sisters with the rest of female society in St. Ogg's.