“Jennie killed him, according to the plan the two of them made.”

“Much of what I told you at Sam’s house was true,” said Jennie. “Richard did write to me after years of silence. He was torn apart by guilt for what he had done to Patrick and Frances, and he saw no way out—no possibility of justice or peace of mind—unless we all paid with our own lives, all four of us who were responsible.”

“He asked you . . . to help him kill Harriet and Ida?” I said, working it out as I spoke.

“Yes. Them, and him, and myself as well. It had to be all of us, he insisted, or else it was meaningless. He did not want to be a murderer but an executioner—he used that word a lot—and that meant that he and I could not avoid punishment. I agreed with him that Harriet and Ida deserved to die. They were evil. But . . . I didn’t want to die, nor did I want Richard dead. It was enough for me that he was truly sorry for his part in Patrick’s death. I . . . I knew it would have been enough for Patrick too, and for any higher authority that might or might not exist. But there was no way to persuade Richard of this. I saw at once that there was no point trying. He was as intelligent as he always had been, but something in his mind had slipped and turned him peculiar, given him weird ideas. All those years of brooding on it, the guilt . . . He had become a strange species of zealot. I knew beyond a shadow of a doubt that he would murder me too if I did not go along with what he was proposing. He didn’t say so explicitly. He didn’t want to threaten me, you see. He was kind to me. What he wanted and needed was an ally. Someone of like mind. He honestly believed I would agree to his scheme because, unlike Harriet and Ida, I was reasonable. He was so certain he was right—that his solution was the only way for all of us. I thought perhaps he was right, but I was afraid. I’m not any more. I don’t know what has changed me. Maybe then, even in my unhappiness, I still entertained the notion that my life might improve. Sadness is different from despair.”

“You knew that you would have to pretend in order to save your life,” said Poirot. “To lie convincingly to Richard Negus—it was your only possible escape from death. You did not know what to do, so you went to Nancy Ducane for help.”