"No, something much simpler than that-" "I don't-" Poirot went on-"No, it knew what no one else seemed to know. It knew she was not its mistress. She looked like its mistress. The housekeeper who was slightly blind and also deaf saw a woman who wore Molly Ravenscroft's clothes and the most recognizable of Molly Ravenscroft's wigs-the one with little curls all over the head. The housekeeper said only that her mistress had been rather different in her manner the last few weeks of her life. 'Same man-different hat,' had been Garroway's phrase. And the thought-the conviction- came to me then. Same wig-different woman. The dog knew-he knew by what his nose told him. A different woman, not the woman he loved-a woman whom he disliked and feared. And I thought, suppose that woman was not Molly Ravenscroft-but who could she be? Could she be Dolly-the twin sister?" "But that's impossible," said Celia.

"No, it was not impossible. After all, remember, they were twins. I must come now to the things that were brought to my notice by Mrs. Oliver. The things people told her or suggested to her. The knowledge that Lady Ravenscroft had recently been in hospital or in a nursing home and that she perhaps had known that she suffered from cancer, or thought that she did. Medical evidence was against that, however. She still might have thought she did, but it was not the case. Then I learned little by little the early history of her and her twin sister, who loved each other very devotedly as twins do, did everything alike, wore clothes alike, the same things seemed to happen to them, they had illnesses at the same time, they married about the same time or not very far removed in time.

And eventually, as many twins do, instead of wanting to do everything in the same fashion and the same way, they wanted to do the opposite. To be as unlike each other as they could.

And even between them grew a certain amount of dislike.

More than that. There was a reason in the past for that.

Alistair Ravenscroft as a young man fell in love with Dorothea Preston-Grey, the elder twin of the two. But his affection shifted to the other sister, Margaret, whom he married.

There was jealousy then, no doubt, which led to an estrangement between the sisters. Margaret continued to be deeply attached to her twin, but Dorothea no longer was devoted in any way to Margaret. That seemed to me to be the explanation of a great many things. Dorothea was a tragic figure. By no fault of her own but by some accident of genes, of birth, of hereditary characteristics, she was always mentally unstable.

At quite an early age she had, for some reason which has never been made clear, a dislike of children. There is every reason to believe that a child came to its death through her action. The evidence was not definite, but it was definite enough for a doctor to advise that she should have mental treatment, and she was for some years treated in a mental home. When reported cured by doctors, she resumed normal life, came often to stay with her sister and went out to India, at a time when they were stationed out there, to join them there. And there, again, an accident happened. A child of a neighbor.

And again, although perhaps there was no very definite proof, it seems again Dorothea might have been responsible for it.

General Ravenscroft took her home to England and she was placed once more in medical care. Once again she appeared to be cured, and after psychiatric care it was again said that she could go once more and resume a normal life. Margaret believed this time that all would be well, and thought that she ought to live with them so that they could watch closely for any signs of any further mental disability. I don't think that General Ravenscroft approved. I think he had a very strong belief that just as someone can be born deformed, spastic or crippled in some way, she had a deformity of the brain which would recur from time to time and that she would have to be constantly watched and saved from herself in case some other tragedy happened." "Are you saying," asked Desmond, "that it was she who shot both the Ravenscrofts?" "No," said Poirot, "that is not my solution. I think what happened was that Dorothea killed her sister, Margaret. They walked together on the cliff one day and Dorothea pushed Margaret over. The dormant obsession of hatred and resentment of the sister who though so like herself, was sane and healthy, was too much for her. Hate, jealousy, the desire to kill all rose to the surface and dominated her. I think that there was one outsider who knew, who was here at the time that this happened. I think you knew. Mademoiselle Zeiie." "Yes," said Zeiie Meauhourat, "I knew. I was here at the time. The Ravenscrofts had been worried about her. That is when they saw her attempt to injure their small son, Edward.

Edward was sent back to school and I and Celia went to my pensionnat. I came back here-after seeing Celia settled in.

Once the house was empty except for myself, General Ravenscroft and Dorothea and Margaret, nobody had any anxiety. And then one day it happened. The two sisters went out together. Dolly returned alone. She seemed in a very queer and nervous state. She came in and sat down at the tea table. It was then General Ravenscroft noticed that her right hand was covered with blood. He asked her if she had had a fall. She said, 'Oh, no, it was nothing. Nothing at all. I got scratched by a rosebush.' But there were no rosebushes on the Downs. It was a purely foolish remark and we were worried.

If she had said a gorse bush, we might have accepted the remark. General Ravenscroft went out and I went after him.

He kept saying as he walked, 'Something has happened to Margaret. I'm sure something has happened to Molly.' We found her on a ledge a little way down the cliff. She had been battered with a rock and stones. She was not dead, but she had bled heavily. For a moment we hardly knew what we could do. We dared not move her. We must get a doctor, we felt, at once, but before we could do that, she clung to her husband. She said, gasping for breath, 'Yes, it was Dolly. She didn't know what she was doing. She didn't know, Alistair.

You mustn't let her suffer for it. She's never known the things she does or why. She can't help it. She's never been able to help it. You must promise me, Alistair. I think I'm dying now. No-no, we won't have time to get a doctor and a doctor couldn't do anything. I've been lying here bleeding to death-and I'm very close to death. I know that, but promise me. Promise me you'll save her. Promise me you won't let the police arrest her. Promise me that she'll not be tried for killing me, not shut up for life as a criminal. Hide me somewhere so that my body won't be found. Please, please, it's the last thing I ask you. You whom I love more than anything in the world. If I could live for you I would, but I'm not going to live. I can feel that. I crawled a little way, but that was all I could do. Promise me. And you, Zeiie, you love me, too. I know. You've loved me and been good to me and looked after me always. And you loved the children, so you must save Dolly. You must save poor Dolly. Please, please. For all the love we have for each other, Dolly must be saved.' " "And then," said Poirot, "what did you do? It seems to me that you must in some way between you-" "Yes. She died, you know. She died within about ten minutes of those last words, and I helped him. I helped him to hide her body. It was a place a little farther along the cliff.

We carried her there and there were rocks and boulders and stones, and we covered her body as best we could. There was no path to it, really, or no way. You had to scramble. We put her there. All Alistair said again and again' was-'I promised her. I must keep my word. I don't know how to do it. I don't know how anyone can save her. I don't know. But-' Well, we did do it. Dolly was in the house. She was frightened, desperate with fright, but at the same time she showed a horrible kind of satisfaction. She said, 'I always knew. I've known for years that Molly was really evil. She took you away from me, Alistair. You belonged to me-but she took you away from me and made you marry her and I always knew one day I should get even with her. I always knew. Now I'm frightened. What'll they do to me-what'll they say? I can't be shut up again. I can't, I can't. I shall go mad. You won't let me be shut up.