On May 1, Beatrice, Otto, and Marianne attend the May Morning dawn celebration on Magdalen Bridge. As they listen to the choir, Beatrice misses Dora, who still has not returned. Afterward, the three meet Henry Hadley and his friends and drink hot toddies on the steps of the Clarendon Building.

Later, Marianne confides in Henry that Charles is the reason Dora hasn’t returned to Oxford. Marianne finds herself attracted to Henry but feels her own past makes any relationship impossible. After the men leave, Otto notes Henry’s interest in Marianne and invites him and his sister for tea. That evening, Marianne returns to her room exhausted and ill. She hallucinates a soldier holding a baby before losing consciousness.

Two days later, an influenza outbreak sweeps through St. Hugh’s. When Marianne does not emerge from her locked room, Otto and Beatrice climb through her window and find her unconscious. Drawing on her wartime nursing experience, Otto takes charge, directing a panicked Beatrice to get help and supplies. As they clean Marianne, Otto discovers stretch marks on her abdomen and breasts, realizing with shock that Marianne has previously given birth.

Beatrice organizes a college-wide response, and news spreads that over a dozen students and instructors, including Miss Jourdain, are ill. The outbreak recedes quickly, and Marianne’s fever breaks the next day. Henry sends her flowers, and Otto teases her about his attention. When Marianne asks if she said anything strange while delirious, Beatrice tells her only that she mentioned her mother. Marianne refuses to go home to recuperate, and Otto announces she will instead visit Dora.

A flashback reveals Marianne’s past. On Armistice Day in November 1918, 18-year-old Marianne is wandering her village of Culham when she encounters Thomas “Tom” Ward, a distraught local soldier. She comforts him, and they share a bottle of liquor before having a sexual encounter by the river. A few weeks later, she learns he has been hospitalized with pneumonia.

In January 1919, realizing she is pregnant, Marianne finds Tom near death in the Radcliffe Infirmary. With his mother’s reluctant consent, Marianne marries him at his bedside to legitimize their child. Her father, the local rector, is devastated but supports her. Two days after the wedding, Tom dies, leaving Marianne a widow.

Otto and Beatrice drive to Berkhamsted to persuade Dora to return to Oxford. They find her looking well at her family home, Fairview. Dora explains that while her parents have allowed her to return to her studies, Oxford has lost its appeal for her because of Charles. She reveals that Charles has written to her, wanting to talk.

Dora leads them on a walk through old wartime practice trenches, the site of her first kiss with Charles, and expresses shame over her youthful naivety. Beatrice and Otto update her on college news, including Beatrice’s run for Junior College Room president, and encourage her to come back. Before they leave, Dora shows them a rare, self-pollinating bee orchid, which Otto declares an “independent woman.” Convinced by her friends, Dora agrees to return and finish the semester.

Back at St. Hugh’s, Dora receives a long, confessional letter from Charles. He explains that he faked his death in France as a survival tactic, repressing all emotion to endure the war. He admits his cruelty toward her was born of shame and jealousy. He announces his plan to transfer to Cambridge.

At a small tea party hosted by the Eights, Dora remains in her room with a headache. The guests include Frank Collingham, Henry Hadley, and Henry’s sister, Lavinia. Henry reveals he will oppose an upcoming Oxford Union motion that women have no place at the university. He asks Beatrice to help him recruit speakers, including her mother.

While giving Lavinia a tour of the college, Marianne learns that Henry is interested in Dora, not her. Devastated, Marianne hides her feelings and tells Lavinia they would make a good match. Later, Otto comforts Beatrice, who is upset by a critical letter from Edith, reassuring her of her worth and the strength of their friendship.

On May 25, the Eights attend the Summer Eights rowing regatta as guests of Frank Collingham. They are delighted to learn that the St. Hilda’s women’s crew is competing against the men’s boats due to a loophole in the rules, and they cheer as the women perform well. Marianne, however, feels withdrawn, still upset about Henry’s interest in Dora.

That evening on the college lawn, Marianne confesses her secret to Otto. Otto reveals she already suspected Marianne had a child after seeing stretch marks while nursing her. Marianne recounts her encounter with the soldier Thomas Ward, their brief marriage, and his death. She explains she hid her past to avoid scandal and secure funding to attend Oxford. She then describes the traumatic birth of her daughter on August 8, 1919. Just as Beatrice approaches, Marianne whispers to Otto that her baby spoke to her through the Ouija board at the séance, having been given the name Constance Olive Ward (abbreviated C. O. Ward).