“What if they are good people?” Joy asks. I try to catch her eye to keep her from breaking Dad’s momentum, but she’s on a riff. “What if there’s just one person who survives an awful crime, like a school shooting, and she has to identify the suspect?”

“Oh sweetie,” Anne says as I would have if she hadn’t beat me to it.

Seeming unaware how tragic it is that a thirteen-year-old knows to ask this, my father lifts his lobster fork and, dispassionately, says, “That scenario introduces other questions, like the effect of trauma. Terror can color eyewitness testimony. And if the witness is injured during the event and loses consciousness, his recollection may be spotty.”

“Emotion,” I say without meaning to, but if Joy thinks of school shootings, I think of that night, right here, twenty years ago. In the aftermath, we were all highly emotional.

My father either doesn’t hear or can’t compute. “Then you have the matter of time between the crime and the trial. And memory. It isn’t stored in the brain intact. It has to be reconstructed. The mind retrieves pieces and puts them together. There’s room for error.”

What he says makes so much sense that I wonder if he and I are wrong and Anne right. He may not have Alzheimer’s at all. Right now, he is perfectly lucid.

But then, setting the fork aside, he frowns and looks around the table. Anne is sucking sweet scraps of meat from the feelers, while Bill has forcefully bent the tail backward and is tugging chunks of meat out with a regular fork. Joy is holding her corn in both hands and eating it row by careful row. I twist off a claw.

Watching me, Dad twists off a claw.

“I never thought of memory that way,” I say, working at the meat. When no one speaks, I realize that either I take the bait, or the opportunity is lost. “Is that what you do, Dad—fit pieces together?”

He removes a piece of meat, dunks it in butter, and eats it. Almost absently, he says, “It is.”

“Do you do it when you think back on that night out on the boat?” I dare ask. I’m aware that Anne has paused to listen.

“Of course, I do,” he says. “I’m the only eyewitness to what happened to Eleanor.”

“Elizabeth,” I whisper.

“Elizabeth,” he whispers back—and how pathetic it is that despite his mistake, I’m pleased that he and I connect.

“It was a long time ago, Dad,” Anne says.

He frowns. “There are so many pieces. I forget some and remember others. Like the weather. Like the sky this afternoon.”

Joy sits up. “Sunny here but stormy in the Vineyard?”