Stevie felt cold despite the heat. She pressed on, in a haze, finding her way on the slatted-wood bridges over the hollows and the silent wood chips, always keeping the lake on her left-hand side, watching it out of one eye, scanning for activity.

Finally, she heard the sound of people talking up ahead. She left the path and wove through the trees until she could see a small group of older women gathered on a bit of sandy beach, speaking in a huddle. From here, she could see the rise of Arrowhead Point, and maybe some people walking around on top, but not much else. She slipped out of the trees, making a bit of noise so she didn’t just pop out of nowhere and scare these strangers. After fitting the microphone into the jack of her phone and tucking it as far into her pocket as she could, she tried to act like she was out taking a casual walk.

“Did something happen?” she said, approaching them and squinting up at the point.

“Woman fell,” said one of the swimmers. “From up there.” She nodded toward Arrowhead Point.

“She just . . . fell?”

“We heard a scream and she kind of tumbled off . . .”

“Like she tripped,” said another swimmer.

“Yeah, she must have tripped.”

This was why you weren’t supposed to let witnesses talk to one another before you spoke to them—when people all see something together and discuss it, details will start to merge. All that seemed to be known was that Allison had screamed and fallen, but the story had already become that she had tripped.

“Barbara—she’s Barbara—she went back to the dock because her shorts were close to the edge and she could get her phone, and I went up to wait for the police. Our friends swam over to try to help, but . . .”

“It was too late,” Barbara said.

“She fell onto those rocks. No one would survive that.”

“Was there anyone else up there?” Stevie said.

“You mean, did someone push her?” Barbara said. “Oh god. No. There was no one. We would have seen. We could see her clearly. There was no one up there but her. She was screaming. She must have tripped.”

“She must have tripped,” the woman who was not Barbara repeated sadly.

Stevie decided not to press Barbara and not-Barbara any further. They were upset, and they had conveyed what they had witnessed—a woman screaming and tumbling off a rocky point.

Not a woman. Allison Abbott. The librarian, the archivist of her sister’s life. The runner. The person who had been through so much, who loved her sister so fiercely.

Stevie felt nauseous and turned back into the woods, walking the way she had come, taking big gulps of soft pine-scented air, trying to let the curtain of greens and browns and pinpoint sunlight soothe her.

Screaming. Tumbling. Her brain, fueled by thousands of hours of absorbing true and fictional crime, painted the scene in vivid detail.