Olivia recalls her father Vincent saying Danny whispered that “the guy who takes a girl to get an abortion is usually the father,” which sparked Vincent’s physical attack on Danny—an altercation Poppy noted in her diary on May 30 and filmed. Olivia cannot learn who took Lydia to the procedure from Vincent, whose memory is fragmented.

Over three days, Olivia revises the fight chapter to include Vincent’s perspective, re-reviews interviews with Mark Randall and Margot Gibson, and re-watches Poppy’s films. She builds a wall timeline: Vincent and Lydia begin dating in February, the bonfire in March, a Pink Floyd concert in April, Lydia’s abortion in early May, school vandalism mid-May, the May 30 fight revealing the abortion, Margot’s account of Vincent threatening Danny with a knife in early June, and the murders on the last day of school with a working schedule (school at 3:00, carnival at 5:00, a 6:45–8:30 meeting in the oak grove with Mr. Stewart, estimated 7:00–7:45 deaths, bodies found at 9:15).

Needing Mr. Stewart’s account, Olivia phones Jack, who says Stewart still lives next door and frequents the gym. Olivia visits, introduces herself, and Stewart invites her in. His house displays decades of student photos and outdoor pursuits; Olivia notes his youthful past appearance and understands why Vincent may have resented him around Lydia.

Stewart describes buying the house in March 1975, liking the Taylor kids, and viewing Vincent as humorous but not athletic. He praises Lydia’s running talent and says after the murders she quit the team and withdrew; he characterizes Lydia’s love for Vincent as intense and unhealthy, and notes the family soon moved. He acknowledges hosting student parties, including an end-of-year party that final week, which he stopped after the murders.

On the day of the murders, Stewart recalls routine details (school, a run, shower, early dinner with his then-girlfriend Amelia) and a plan for a brief carnival visit. At the carnival, he saw Vincent and Lydia in a heated argument; Lydia was crying, and Vincent was angrier than Stewart had ever seen. Stewart offered help but says Vincent resisted until Lydia urged him to mediate. They walked to the oak grove to talk privately.

Pressed about the argument’s subject, Stewart demurs, but when Olivia asks directly about the abortion, he admits he took Lydia to the procedure, claims no regrets, and insists he was not the father. He says he assumed the baby was Vincent’s and doubts Danny’s involvement, asserting Lydia disliked Danny and that Danny tormented Vincent. Olivia raises the possibility of nonconsensual involvement by Danny; Stewart says Lydia’s behavior did not suggest assault to him.

Stewart offers no further specifics and frames the case as long-painful and senseless. When Olivia asks who he thinks killed Poppy and Danny, he suggests the hitchhiker who picked up Poppy earlier, citing timing and the man’s knowledge of the carnival. Olivia exits with a recorded account that corroborates the oak grove meeting window, confirms Stewart drove Lydia to the abortion, and reinforces the intensity of Vincent and Lydia’s conflict that night.