Big things are on the way. Lady Denham’s garden party is approaching, which means Clara and her new son George must decamp to a cottage to stay out of sight, although Lady Denham will allow them to stay there for some time. Captain Carter has received Colonel Lennox’s permission to ask Alison to marry him, to Captain Fraser’s chagrin: Fraser has seen Carter fall in love with several other women, plus he knows Carter is lying to Alison about his experience in battle and knowledge of poetry.
Augusta will make her long-awaited debut at the garden party, at her uncle Alexander’s side. (He himself hasn’t been at a social event in a decade.) He is a changed man since he has employed Charlotte as governess; he even unlocked and had his late wife’s spinet tuned for the girls to play. He also allows Augusta to choose one of Lucy’s dresses for the party. While she tries them on, Leonora hugs her: it’s like she is hugging her mother.
Charles has begun work on a portrait of Georgiana, but the process of her sitting for a sketch—under the supervision of Miss Hankins—is difficult. Charles wants her to show her true self; she is frosty towards him. When he asks her personal questions, like about her dreams, she lets her mask drop for a minute to chastise him and leaves in a huff.
Georgiana has learned why Sidney was in Antigua on her behalf. One of her father’s relatives tried to steal her inheritance by arguing that her descent from a slave—her mother—disqualified her from the inheritance. His effort failed thanks to Sidney, but Georgiana fears other relatives will emerge to question her legitimacy, just because she is Black.
Clara’s son is actually born out of wedlock, and Esther believes she is simply playing at being a mother for Lady Denham’s (and her fortune’s) sake. Esther understands what the baby needs more intuitively than Clara, and is jealous of Clara’s good fortune in being able to have a child. When Esther cries while holding George, Clara finally begins to understand Esther’s fervent wish to have a baby of her own.
Esther’s kindness towards George and Clara makes Clara extra skeptical when Edward visits her during Lady Denham’s garden party, to which he was not invited, and proposes. A marriage would help George—and Clara and Edward, via Lady Denham’s fortune.
Clara is worried about Esther, but Edward says he has taken care of her: he has bribed a footman to give him any letters addressed to her. She will believe her husband has abandoned her because she could not produce an heir, eventually losing her sanity—and thus her share of Lady Denham’s fortune. She is not being kind, Edward tells Clara; she is trying to use Clara just like Edward and Clara have used each other.
It seems that Colonel Lennox might similarly be gaming Tom. Mary keeps asking Tom to speak to the Colonel about the army’s unsettled debts, but Tom’s own gambling debt to the army—which no one else knows about—prevents him from making any headway. At the garden party, Lennox also airily dismisses Tom’s idea to build a permanent barracks in Sanditon, in front of everyone; he’s not yet convinced.
Lennox’s interactions with Alexander at the party are even colder. He is disappointed that Charlotte has not heeded his warning about Alexander but tells her that he will be cordial during the party. Alexander wants to leave because of Lennox’s presence, but Charlotte convinces him to stay for Augusta’s sake. Unable to breathe in her too-tight corset, Augusta faints, and Lennox catches her, to Alexander’s horror. After Augusta recovers, Lennox quietly taunts Alexander, telling her that holding Augusta was like having Alexander’s late wife Lucy in his arms again.
In casual conversation, Charlotte learns from Lennox that Carter has never seen battle, despite what he has told Alison. But when she tells her sister, Alison lashes out and refuses to believe her. She also ignored Fraser’s urging of caution, even after he opened up to her about loving a woman whom he cannot name, whose heart is with another. Fraser also angered Alison by calling her a farmer’s daughter.
Carter rows Alison down the river and proposes to her. Thrilled, she says yes, but falls overboard in her excitement. Rather than dive in after her, he yells for help. Fraser saves Alison, who is aghast that Carter did nothing. You’re nothing but a coward, and everything you have told me is a lie, she tells Carter, criticizing Fraser for knowing that Carter was being dishonest and not telling her.
Lady Denham has ordered a massive cake for her party, but when she asks Arthur to cut it he refuses, in support of Georgiana’s sugar boycott. Georgiana takes the chance to explain and defend the boycott, and all the guests decline to eat any cake. Charles watches and tells Georgiana that he wishes to capture her in that moment, while her passion is up. She gives him permission, but asks to do it somewhere out of sight.
She finally answers his question about what she dreamed of: her former lover, Otis, who disappointed her in the end. Otis is the reason she is reluctant to let her guard down. Charles nearly kisses Georgiana, but is interrupted by the frantic appearance of Miss Hankins and Mary.
Edward makes his own unwelcome appearance at the party to announce that he and Clara are getting married. Esther sees through the ploy to gain Lady Denham’s fortune, and goes to speak to Clara. Clara says Edward has changed, and admits that she is scared to allow herself to love George. Esther begins to show her how, having Clara look at George and hold him close. You’re a better woman than you think, Esther tells her.
Lennox challenges Alexander to an archery competition, and he reluctantly accepts after Lady Denham teases him—his father was a great archer, although Alexander dislikes being compared to him. The two men are equally matched, but Lennox asks Charlotte to take his final shot. She hits the bull’s-eye. She misfires when Alexander asks the same.
Lennox taunts Alexander, who grabs Augusta and leaves. Charlotte follows, and Alexander angrily tells her not to spend any more time with Lennox. She responds that he doesn’t own her, and he drives off. Lennox watches with a smirk.