The narrative shifts to Lady Helen Clyde, who is staying with her sister Penelope, brother-in-law Harry Rodger, and their children while Penelope recovers from the birth of their newest child. Penelope’s son, Christian, is enthusiastic and vocal, reciting the names of American states, while her daughter, Perdita, remains quiet and withdrawn. When their father, Harry Rodger, arrives home—looking unwell and unshaven—Christian rushes to greet him, but Perdita shrinks away.

In the kitchen, Lady Helen confronts Harry about his absence and treatment of Penelope. He dismisses her concerns. Penelope appears, weak and disheveled, with milk stains on her dressing gown. A bitter argument erupts between husband and wife about the decision to have a third child. Penelope accuses Harry of pressuring her into pregnancy, making her feel like a “breeding machine” with no identity. Harry counters that she made the final decision and accuses her of wallowing in self-pity. He leaves as the baby cries and Christian screams.

Lady Helen holds her weeping sister, realizing Penelope gave up her career to have children, became dependent, and believed she had to hold onto her husband by giving him what he wanted. Now Penelope is trapped, living a life she isn’t sure she wants, unable to redefine herself beyond her role as a mother.

At lunch in a pub, Sergeant Havers reports that Sarah’s alibi checks out—two neighbors saw her leaving her house shortly before 7:00 am on Monday. Lynley tells Havers he believes he saw Sarah at St. Stephen’s College on Monday night, emerging from the shadows near the graveyard. Havers notes that Sarah didn’t know the victim was Elena and suggests that the woman Lynley saw could have been anyone, even Thorsson, in poor light.

Lynley speculates that Anthony’s rooms are in Ivy Court, and Sarah may have gone to see him. Havers proposes an affair between Sarah and Weaver, but Lynley notes the timing doesn’t fit—the woman was in and out in under five minutes, and if they were meeting for a romantic tryst, why wouldn’t Weaver go to Grantchester instead? They debate the coincidence of Sarah finding the body and then appearing at the college, and Havers argues that Sarah went to see Anthony for reasons unrelated to the murder. She questions whether Lynley is biased because of Sarah’s resemblance to Lady Helen.

Havers points out that the timeline makes it nearly impossible for Sarah to be the killer and argues for pursuing Thorsson as the stronger candidate with an obvious motive, means, and opportunity. Lynley acknowledges her solid reasoning and agrees to compromise: Havers will check Thorsson’s neighbors and investigate the Seymour Street address while he confirms whether the Ivy Court rooms belong to Anthony.

At St. Stephen’s, Lynley finds the rooms are indeed Anthony’s. Inside, he encounters Adam Jenn, Anthony’s graduate student who shares the study. Lynley questions Adam, who reveals Anthony wasn’t in the study Sunday evening, contradicting Weaver’s claim. Adam nervously insists Anthony might have returned later to work on research, defending his mentor.

Adam admits Anthony asked him to escort Elena occasionally to keep her away from Gareth Randolph, a deaf student from Queens’ College. Adam reveals Elena treated her father’s devotion as a joke. When asked if he and Elena were romantically involved, Adam responds with a vehement no, explaining he had no time for “women’s complications.” He says Elena took everything as a joke, including the idea that her father loved her. Anthony believed he had to keep proving himself to Elena, and he was so intent on this goal that he never really saw her completely.

At the funeral home, Anthony and his ex-wife Glyn meet with Mr. Beck to arrange Elena’s burial. The police still have the body for autopsy. When Mr. Beck mentions a possible viewing, Glyn insists on it, wanting everyone to see the damage done to Elena. In the showroom, Glyn chooses the cheapest coffin, a pressed wood model with no protection. Anthony objects, but Glyn refuses his money, accusing him of abandoning Elena and having no rights. She begins to write a check.

Anthony accuses Glyn of using Elena’s death for revenge rather than genuinely grieving. Glyn strikes him, knocking his spectacles off, then breaks down weeping over the coffin. She reveals her deepest pain: she can never have another child while Anthony still can. Anthony feels compassion despite their enmity, understanding she’s lost not only Elena but any possibility of starting again. When he tries to comfort her, she rejects him violently, falling and tearing the coffin’s flimsy covering.

Lynley runs Elena’s route to the island, completing it in seven minutes despite being out of shape after years of smoking. He estimates Elena would have done it in five to ten minutes, placing her at the island no later than 6:25 am. At the boat repair shed on the north end of the island, three workers are resentful of police presence and complain about town-and-gown tensions.

Examining the crime scene, Lynley notes everything has been swept up except a fire ring and the impression of a bottle in the mud. He wonders if an unopened wine bottle could have been the weapon—filled with wine and used to beat her, then emptied, washed, and tamped into the earth to look like rubbish. He smells vomit on the riverbank where Sarah reported getting sick after she saw the body. At the causeway bridge, he realizes a runner from St. Stephen’s would have three route options, meaning the killer must have known which path Elena would take.

Back at the college, Lynley meets Havers, who reveals the autopsy results: Elena was eight weeks pregnant.

Havers explains the pregnancy’s implications, noting that the unused birth control pills suggest Elena was trying to get pregnant deliberately. Havers presents Superintendent Sheehan’s theory: Elena was involved with a senior member of the college, became pregnant, wanted marriage, but he feared the damage to his career and killed her when she threatened to expose him. The Seymour Street address was a health clinic where Elena had a pregnancy test on the Wednesday before her death. Havers argues that this evidence points to Thorsson as a suspect and entrapment as a motive.

Lynley counters that Elena might simply have stopped taking the pills because there was no man in her life, or she might have been raped. He insists Thorsson isn’t alone as a suspect. A message arrives for Havers from her mother’s caregiver informing her that her mother is out of sorts. Lynley orders her to go home to London, saying he’ll handle things in Cambridge.

Lynley goes to question Justine. She’s dressed formally and reluctant to speak without Anthony present. Inside, Lynley asks when Elena arrived in Cambridge for Michaelmas term. Justine says she arrived around mid-September, as Elena attended a faculty party on the 13th. When Lynley tells her Elena was eight weeks pregnant, Justine isn’t surprised because she knew Elena was sexually active and flaunted it, wanting people—especially her father—to know.

Justine reveals she tried to counsel Elena about hygiene and birth control, but Elena claimed she’d been on the pill since age 14 when she began sleeping with the father of a school friend. Justine says Elena wanted to prove she was the normal daughter Anthony wanted while simultaneously taking revenge by becoming pregnant, likely by a deaf man—something her father opposed. Justine can’t explain the fish symbol but confirms that Elena’s date to the Christmas Ball that December was Gareth.

When Lynley points out that Justine and Anthony have no children, she deflects, but her discomfort is evident. When asked about Sarah, Justine fumbles briefly before denying knowing her. After Lynley leaves, Justine reflects on her childless marriage. Anthony refuses to have another child because he fears betraying Elena by producing a replacement. Justine realizes Elena’s death removes the reason for their marriage—providing Elena with a stable home and example of lasting love—and that they’ve been living a lie.

Justine drives to Midsummer Common with Townee, the family’s Irish setter, and finds Victor Radcliffe finishing a rowing session. She confronts him with the DeaStu’s flyer about Elena’s death. Victor admits he didn’t know until seeing it that morning. He reveals Elena was with him Sunday night, and when Justine asks if Elena told him about the pregnancy, he confirms she did. When asked what he planned to do, Victor says he planned to marry Elena. Justine asks pointedly where Victor’s wife, Rowena, was Sunday night while Victor was with Elena.