Lucy Deane, wearing mourning for the death of her mother, sits in her parlor with her suitor, Stephen Guest, at her knees. Stephen is the son of Mr. Deane's senior partner. Stephen is handsome, rich, and leisurely. The two are flirtatious and secure in their love, though no betrothals have been made yet. Lucy tells Stephen of the imminent arrival of her cousin Maggie, who has had a hard life and has been serving as a governess in another town. Lucy allows Stephen to assume that Maggie is fat, blond, and dull-witted like Mrs. Tulliver, who now lives at the Deane's. Lucy is worried that Maggie will not want to see Philip Wakem, a friend of Lucy and Stephen's who comes often to sing with them. Lucy writes a note to Philip for Stephen to take to him. Lucy and Stephen sing several duets before Stephen must leave.
After Stephen's departure, Lucy takes a quick glance at herself in the mirror. Though beautiful, Lucy is not truly vain, for she is too benevolent and filled with thoughts of others to be vain. Now Lucy rehearses in her mind the preparations for Maggie's arrival—Lucy's favorite cousin must have the best of everything and a truly relaxing visit.
Though Lucy is only the daughter of his father's lesser partner, Stephen is sure of his love for her. Lucy is exactly the kind of woman he has always admired—beautiful and kind to others, even other women.
Lucy and Maggie sit in Lucy's parlor—Lucy is describing Stephen Guest. Lucy remarks on Maggie's beauty, which seems enhanced by her "shabby clothes." Maggie envies Lucy's happiness, which is gained from the happiness of others. Maggie admits to being regularly unhappy and sometimes getting angry at the sight of happy people. Maggie's years of renunciation had ended, and she has been experiencing "desire and longing," contributing to her unhappiness. Lucy brings up the topic of Philip Wakem with Maggie, who assures Lucy that she, Maggie, does not think harshly of Philip as Tom does. Maggie is about to explain her promise to Tom not to see Philip, when the doorbell rings and Stephen Guest enters.
Stephen is quickly fascinated by Maggie's tall, dark, beauty, and her frankness. Maggie quickly realizes that Stephen had drawn a satirical portrait of her in his head before meeting her. Maggie is frank about her annoyance at his conventional compliment to recover himself and also satirical about Stephen's obvious self-assurance. Maggie is also frank about her own poverty, to Lucy's dismay and Stephen's interest. Stephen changes the subject to a variety of things—the upcoming town bazaar, the charity of the minister, Dr. Kenn, the next book for the Book Club—in hopes that Maggie will look at him as he speaks.
Stephen proposes a boating trip. While Maggie gets her bonnet, Lucy informs Stephen that Maggie will see Philip, and Stephen informs Lucy that Maggie is too tall and "fiery"—not his "type" of woman. Yet, Stephen remains intrigued by Maggie, because she is so unlike other women. He looks forward to having to take her hand during the boat-ride. When Stephen catches Maggie, who slips getting out of the boat, Maggie herself feels charmed by the protective touch.
Back at the Deanes, after the boat-ride, Mr. and Mrs. Pullet are visiting so that Mrs. Pullet might donate a formal dress to Maggie. The group openly discusses the beauty of Maggie's arm shape and the tragedy of her unsophisticated brown skin.
After an evening of Stephen's singing, Maggie goes up to her bedroom, too excited by the music and the vague atmosphere of romance to sleep. Lucy comes in and asks her opinion of Stephen. Maggie teases that he is too self- confident—"a lover should not be so much at ease." At Lucy's mention of more music with Philip Wakem, Maggie remembers to tell her that she, Maggie, has promised Tom not to see Philip. Lucy offers to speak to Tom, but Maggie insists upon going herself. Maggie explains the story of her relationship with Philip to Lucy. Lucy is enthusiastic about Maggie and Philip—she vows to find a way for them to be married.
Maggie goes to Bob Jakin's house, where Tom now lives. Bob's new wife greets Maggie, and Bob soon comes in. Bob speaks to Maggie of Tom's glumness and drops a hint that Tom might be in love with Lucy, for whom Tom just acquired a new dog.
Tom comes in, and Maggie asks him to absolve her from her promise not to see Philip. Tom coldly agrees, and Maggie reassures him that she will only see Philip in the company of others— "There will never be anything secret between us again." Tom reminds her that his feelings about Philip remain the same and that if she means to make Philip a lover, she must give Tom up. Tom tells Maggie that he has "no confidence" in her, and Maggie begins to cry. Tom explains to Maggie that she is always acting in extremes and assuming she knows best. Maggie inwardly critizes Tom for being "narrow and unjust." Tom brings up the scene between their father and Wakem just before Mr. Tulliver's death as a reason for Maggie to forget a relationship with Philip, and Maggie again reassures him that she has given up thinking of Philip as a lover.
The two reconcile before Tom must return to work.
There are two tragedies in The Mill on the Floss. Mr. Tulliver's tragedy ended with his death at the end of Book Fifth. Maggie's tragedy takes over the novel beginning with Book Sixth. Several years have passed between the end of Book Fifth and the beginning of Book Sixth, and Maggie is now nearly a grown woman at nineteen. Descriptions in the opening of Book Sixth of the grown Maggie emphasize her newly sensuous body—she is tall and broad, with curvaceous arms and fleshy, red lips. Maggie has become a figure of longing—we learn that in the years between Book Fifth and Sixth, Maggie has given up her pious self-denial and has allowed herself to wish for things in her life. These physical and emotional markers of the young adult Maggie are integral to understanding her actions later in the novel.
Thus far in The Mill on the Floss, the novel has mainly been set at the mill or nearby, with the exception of Tom's school years at Lorton. With the opening of Book Sixth, however, the setting shifts to St. Ogg's, and with the setting change the novel's social background widens. The early dramas of Maggie's life played out only against the backdrop of her family, immediate and extended, but in St. Ogg's the presence of a whole community, and an accompanying set of social values and conventions is implicit. Just as Maggie seems to be more beautiful in her worn clothing, she also gains in appeal against the social backdrop of St. Ogg's. Because she is not studied in high societal conventions, her innocence and genuineness make her seem harmless (and therefore appealing) to competitive women and freshly attractive to men.
Book Sixth reintroduces Lucy Deane as a character. As children, Lucy stood for Maggie's opposite—light where she was dark, agreeable where she was contrary, docile where she was impetuous. In their maturity, the polarity between Lucy and Maggie still remains to some extent—Lucy enjoys leisure and money while Maggie works for a living. Lucy has remained petite where Maggie has grown tall. During their childhood, Maggie was never quite jealous of Lucy herself but often envied what Lucy had—the stature and features of a little queen or Tom's attention. Here again, Maggie has no direct enmity for Lucy, but Maggie is potentially put in a position of envy as regards her lifestyle and relationships.
Book Sixth introduces us to Stephen Guest. Stephen is depicted as overly self- assured and artificial, yet he is also shown to be perceptive. Stephen and Maggie's mutual interest seems a related to a sense of novelty on each side—Stephen has never met a woman as frank and earnest or from the same social background as Maggie, and Maggie has never enjoyed the close proximity of a strong male presence. Stephen's near obsession with her upon their first meetin is connected to the quality of Maggie's eyes. As they were in the descriptions of her as a child Maggie's eyes continue to be associated with some sort of witchcraft, or at least, power over others.
As becomes clear, Philip will also reappear in this book. Maggie's struggles remain mainly internal but also become externalized to some extent in Book Sixth, as embodied by three very different men—Stephen, Philip, and Tom.