He opened it with his little letter-opener. I looked on with interest since he seemed so moved to pleasure about it. There was a letter and a fairly thick enclosure.

Poirot read the former through twice, then he looked up.

‘Would you like to see this, Hastings?’

I took it from him. It ran as follows:

Dear M. Poirot, – I was much touched by your kind – your very kind letter. I have been feeling so bewildered by everything. Apart from my terrible grief, I have been so affronted by the things that seem to have been hinted about Carlotta – the dearest, sweetest sister that a girl ever had. No, M. Poirot, she did not take drugs. I’m sure of it. She had a horror of that kind of thing. I’ve often heard her say so. If she played a part in that poor man’s death, it was an entirely innocent one – but of course her letter to me proves that. I am sending you the actual letter itself since you ask me to do so. I hate parting with the last letter she ever wrote, but I know you will take care of it and let me have it back, and if it helps you to clear up some of the mystery about her death, as you say it may do – why, then, of course it must go to you.

You ask whether Carlotta mentioned any friend specially in her letters. She mentioned a great many people, of course, but nobody in a very outstanding way. Bryan Martin whom we used to know years ago, a girl called Jenny Driver, and a Captain Ronald Marsh were, I think, the ones she saw most of.

I wish I could think of something to help you. You write so kindly and with such understanding, and you seem to realize what Carlotta and I were to each other.

Gratefully yours,

Lucie Adams

P.S. An officer has just been here for the letter. I told him that I had already mailed it to you. This, of course, was not true, but I felt somehow or other that it was important you should see it first. It seems Scotland Yard need it as evidence, against the murderer. You will take it to them. But, oh! please be sure they let you have it back again some day. You see, it is Carlotta’s last words to me.

‘So you wrote yourself to her,’ I remarked as I laid the letter down. ‘Why did you do that, Poirot? And why did you ask for the original of Carlotta Adams’ letter?’ 

He was bending over the enclosed sheets of the letter I mentioned.

‘In verity I could not say, Hastings – unless it is that I hoped against hope that the original letter might in some way explain the inexplicable.’

‘I don’t see how you can get away from the text of that letter. Carlotta Adams gave it herself to the maid to post. There was no hocus pocus about it. And certainly it reads as a perfectly genuine ordinary epistle.’

Poirot sighed.

‘I know. I know. And that is what makes it so difficult. Because, Hastings, as it stands, that letter is impossible.’

‘Nonsense.’

‘Si, si, it is so. See you, as I have reasoned it out, certain things must be – they follow each other with method and order in an understandable fashion. But then comes this letter. It does not accord. Who, then, is wrong? Hercule Poirot or the letter?’

‘You don’t think it possible that it could be Hercule Poirot?’ I suggested as delicately as I was able.

Poirot threw me a glance of reproof.

‘There are times when I have been in error – but this is not one of them. Clearly then, since the letter seems impossible, it is impossible. There is some fact about the letter which escapes us. I seek to discover what that fact is.’

And thereupon he resumed his study of the letter in question, using a small pocket microscope.

As he finished perusing each page, he passed it across to me. I, certainly, could find nothing amiss. It was written in a firm fairly legible handwriting and it was word for word as it had been telegraphed across.

Poirot sighed deeply.

‘There is no forgery of any kind here – no, it is all written in the same hand. And yet, since, as I say, it is impossible–’

He broke off. With an impatient gesture he demanded the sheets from me. I passed them over, and once again he went slowly through them.

Suddenly he uttered a cry.

I had left the breakfast table and was standing looking out of the window. At this sound, I turned sharply.

Poirot was literally quivering with excitement. His eyes were green like a cat’s. His pointing finger trembled.

‘See you, Hastings? Look here – quickly – come and look.’

I ran to his side. Spread out before him was one of the middle sheets of the letter. I could see nothing unusual about it.

‘See you not? All these other sheets they have the clean edge – they are single sheets. But this one – see – one side of it is ragged – it has been torn. Now do you see what I mean?This letter was a double sheet, and so, you comprehend,one page of the letter is missing.’ 

I stared stupidly, no doubt.

‘But how can it be. It makes sense.’

‘Yes, yes, it makes sense. That is where the cleverness of the idea comes in. Read – and you will see.’

I think I cannot do better than to apprehend a facsimile of the page in question.

‘You see it now?’ said Poirot. ‘The letter breaks off where she is talking of Captain Marsh. She is sorry for him, and then she says: “He enjoyed my show very much.” Then on the new sheet she goes on: “he said…” But, mon ami, a page is missing. The “he” of the new page may not be the “He” of the old page. In fact it is not the “He” of the old page. It is another man altogether who proposed that hoax. Observe, nowhere after that is the name mentioned. Ah! C’est epatant! Somehow or other our murderer gets hold of this letter. It gives him away. No doubt he thinks to suppress it altogether, and then – reading it over – he sees another way of dealing with it. Remove one page, and the letter is capable of being twisted into a damning accusation of another man – a man too who has a motive for Lord Edgware’s death. Ah! it was a gift! The money for the confiture as you say! He tears the sheet off and replaces the letter.’

I looked at Poirot in some admiration. I was not perfectly convinced of the truth of his theory. It seemed to be highly possible that Carlotta had used an odd half sheet that was already torn. But Poirot was so transfigured with joy that I simply had not the heart to suggest this prosaic possibility. After all, he might be right.

I did, however, venture to point out one or two difficulties in the way of his theory.

‘But how did the man, whoever he was, get hold of the letter? Miss Adams took it straight from her handbag and gave it herself to the maid to post. The maid told us so.’

‘Therefore we must assume one of two things. Either the maid was lying, or else, during that evening, Carlotta Adams met the murderer.’

I nodded.

‘It seems to me that that last possibility is the most likely one. We still do not know where Carlotta Adams was between the time she left the flat and nine o’clock when she left her suitcase at Euston station. During that time, I believe myself that she met the murderer in some appointed spot – they probably had some food together. He gave her some last instructions. What happened exactly in regard to the letter we do not know. One can make a guess. She may have been carrying it in her hand meaning to post it. She may have laid it down on the table in the restaurant. He sees the address and scents a possible danger. He may have picked it up adroitly, made an excuse for leaving the table, opened it, read it, torn out the sheet, and then either replaced it on the table, or perhaps given it to her as she left, telling her that she had dropped it without noticing. The exact way of it was not important – but two things do seem clear. That Carlotta Adams met the murderer that evening either before the murder of Lord Edgware, or afterwards (there was time after she left the Corner House for a brief interview). I have a fancy, though there I am perhaps wrong, that it was the murderer who gave her the gold box – it was possibly a sentimental memento of their first meeting. If so, the murderer is D.’