On Guy Fawkes Day, Otto wakes with a severe toothache. Marianne arranges a dentist appointment, and Miss Stroud chaperones them. The bus ride and the dental surgery trigger traumatic war-related memories for Otto, who becomes terrified. The dentist extracts the broken tooth while she is under nitrous oxide.

The following Monday, after a weekend at home, Marianne joins her friends, who are now calling themselves “the Eights,” for their regular study session at the Radcliffe Camera library. Afterward, they are targeted in a prank arranged by the students at the adjacent Brasenose College. A student cries for help, luring the women into the college lodge while accomplices steal Marianne’s and Otto’s bags from their bicycle baskets. A handsome student, Arthur Motson-Brown, then approaches, claiming the theft is a tradition for a dining society. He returns their bags and recognizes Otto as the sister of a London socialite, Vita Wallace-Kerr. However, another student arrives and reveals that Motson-Brown was part of the prank, which he devised to meet them. Beatrice is furious and leaves, but Otto is amused. Motson-Brown gives his card to Otto and Dora, inviting them for tea.

The fifth week of the semester is marked by Armistice commemorations. Beatrice is deeply moved by a newsreel of the Unknown Warrior’s burial. While out with her friends, she witnesses a woman steal food from a shop, which makes her reflect on post-war poverty. Later, Dora speaks for the first time about her brother, George, and her fiancé, Charles, who were killed two weeks apart at the Battle of Cambrai. Dora reveals to herself that she finds solace in imagining Charles is the Unknown Warrior.

That night, a drunk Otto gets locked out and climbs into Marianne’s room. She confesses that her mother wants her to leave Oxford to marry a man named Teddy, and starts crying. Otto has been sneaking out to parties, using alcohol to cope with her war trauma. Soon after, her mathematics instructor, Miss Brockett, delivers a warning from the principal, Miss Jourdain, about Otto’s behavior. Miss Brockett, revealing she was also a Voluntary Aid Detachment (VAD) nurse, offers to talk with Otto about her war experiences and encourages her to join the hockey team. Shaken by the conversation, Otto signs up for hockey, then sees a new notice from Miss Jourdain forbidding unchaperoned visits to men’s rooms under penalty of expulsion.

In a flashback to June 1915, 15-year-old Dora visits her brother, George, at Jesus College, Oxford, with their mother. George confides in Dora that he is failing his divinity exams and plans to enlist in the army to avoid being expelled from the university. While at the college, Dora feels self-conscious around the male students and meets George’s quiet friend, Frank Collingham.

Dora’s visit is disrupted when she gets her first period. Forced to tell her mother, she is forbidden from joining the planned boating trip and is sent back to her hotel room. A maid brings her a package of sanitary products. Feeling trapped, humiliated, and indignant about her new physical reality, Dora tears the boxes and leaflets to pieces in a fit of rage.

In the sixth week of the semester, Dora receives an invitation for tea at Jesus College from Frank Collingham, her late brother George’s friend, who recognized her in town. With their chaperone, Miss Cox, the Eights visit his rooms. After tea, Frank takes them to see the college’s new war memorial, which is still under construction. He unveils a large oak panel carved with the names of the dead, and Dora sees her brother’s name, G. P. Greenwood, listed among them.

Meanwhile, Marianne has been secretly caring for the college cat and its newborn kittens in her room. When the kittens become too disruptive, they suddenly disappear. Marianne suspects the scout, Maud, had something to do with it but cannot ask. She then receives a formal warning from Miss Jourdain for keeping animals on the premises. As Marianne leaves for her weekend home, Maud secretly intercepts her at the train station and gives her a basket containing one of the kittens.

Otto hosts a séance in her room with wine and a Ouija board. After some jokes, the planchette begins to move, spelling out “C-O-W-A-R-D.” Marianne weeps. Otto, enraged, accuses her friends of a cruel prank, throws the board in the fire, and orders Marianne to leave. After Marianne exits, Otto confesses that she considers herself a coward. She reveals that during the war, she failed her probation as a VAD nurse after only six weeks because the experience was overwhelming. This experience continues to haunt her.

Beatrice tries to comfort Otto by deconstructing the word “coward,” but Otto rebuffs her. Hurt, Beatrice leaves and finds Marianne in the hallway. Marianne, though physically ill, appears radiant and tells Beatrice that she received a message from an unspecified girl. Just then, Miss Jourdain appears in the corridor and discovers the scene.

A flashback details Otto’s traumatic VAD service in January 1918. Posted to a hospital for officers at Somerville College, Otto found the work of a probationary nurse horrifying. She experienced frequent nightmares and a mental health crisis, which contributed to the failure of her probation. Her influential father then arranged her reassignment as a driver in Oxford.

One day, Otto assists an elderly woman, Miss Rogers, a Classics instructor at St. Hugh’s College, who was knocked off her bicycle. Miss Rogers invites Otto for tea, mistakenly assuming she is a student. Otto is inspired by the independent and intellectual Miss Rogers, who recounts her own fight for an education in a system that denied her a place at a men’s college despite her academic excellence. This encounter motivates Otto to seek a university education herself. After her service ends, she prepares for the entrance exams and is accepted to study mathematics at St. Hugh’s.

In the final week of the semester, Miss Jourdain gives the Eights a lenient punishment for drinking alcohol, restricting them to an 8 pm. curfew. The atmosphere in the group remains tense, as Marianne has withdrawn from them ever since the Ouija board incident. Meanwhile, Frank Collingham gives Dora a book and asks to write to her over Christmas; seeing a practical path to marriage, she agrees. Dora also learns she must retake a mathematics exam she has failed. She feels intellectually inadequate compared to her friends.

On their last night, the Eights get permission to dine at Otto’s aunt’s house, which is empty for the winter. They enjoy a lavish meal and exchange Christmas gifts. Marianne gives each friend a thoughtfully chosen, framed poem she typed herself. In return, Otto gives Marianne a one-pound note for books, which she sees as a generous and understanding gift. The evening of friendship and gift-giving reaffirms their bond. Marianne feels a momentary urge to reveal her secret to them but decides against it.