“When MacQueen first learned that the letter which had been so carefully burnt had in part escaped destruction, and that the word Armstrong was exactly the word remaining, he must at once have communicated his news, to the others. It was at this minute that the position of Countess Andrenyi became acute, and her husband immediately took steps to alter the passport. It was their second piece of bad luck!

“They one and all agreed to deny utterly any connection with the Armstrong family. They knew I had no immediate means of finding out the truth, and they did not believe that I should go into the matter unless my suspicions were aroused against one particular person.

“Now there was one further point to consider. Allowing that my theory of the crime was the correct one, and I believed that it must be the correct one, then obviously the Wagon Lit conductor himself must be privy to the plot. But if so, that gave us thirteen persons, not twelve. Instead of the usual formula ‘Of so many people one is guilty,’ I was faced with the problem that of thirteen persons one and one only was innocent. Which was that person?

“I came to a very odd conclusion. I came to the conclusion that the person who had taken no part in the crime was the person who would be considered the most likely to do so. I refer to Countess Andrenyi. I was impressed by the earnestness of her husband when he swore to me solemnly on his honour that his wife never left her compartment that night. I decided that Count Andrenyi took, so to speak, his wife’s place.

“If so, then Pierre Michel was definitely one of the twelve. But how could one explain his complicity? He was a decent man who had been many years in the employ of the company – not the kind of man who could be bribed to assist in a crime. Then Pierre Michel must be involved in the Armstrong case. But that seemed very improbable. Then I remembered that the dead nursery-maid had been French. Supposing that that unfortunate girl had been Pierre Michel’s daughter. That would explain everything – it would also explain the place chosen for the staging of the crime. Were there any others whose part in the drama was not clear? Colonel Arbuthnot I put down as a friend of the Armstrongs. They had probably been through the War together. The maid, Hildegarde Schmidt – I could guess her place in the Armstrong household. I am, perhaps, over greedy, but I sense a good cook instinctively. I laid a trap for her – she fell into it. I said I knew she was a good cook. She answered: ‘Yes, indeed, all my ladies have said so.’ But if you are employed as a lady’s-maid your employers seldom have a chance of learning whether or not you are a good cook.

“Then there was Hardman. He seemed quite definitely not to belong to the Armstrong household. I could only imagine that he had been in love with the French girl. I spoke to him of the charm of foreign women – and again I obtained the reaction I was looking for. Sudden tears came into his eyes, which he pretended were dazzled by the snow.

“There remains Mrs. Hubbard. Now Mrs. Hubbard, let me say, played the most important part in the drama. By occupying the compartment communicating with that of Ratchett she was more open to suspicion than anyone else. In the nature of things she could not have an alibi to fall back upon. To play the part she played – the perfectly natural, slightly ridiculous American fond mother – an artist was needed. But there was an artist connected with the Armstrong family: Mrs. Armstrong’s mother – Linda Arden, the actress…”

He stopped.

Then in a soft rich dreamy voice, quite unlike the one she had used throughout the journey, Mrs. Hubbard said:

“I always fancied myself in comedy parts.”

She went on, still dreamily:

“That slip about the sponge-bag was silly. It shows that you should always rehearse property. We tried it on the way out – I was in an even-number compartment then, I suppose. I never thought of the bolts being in different places.”

She shifted her position a little and looked straight at Poirot.

“You know all about it, M. Poirot. You’re a very wonderful man. But even you can’t quite imagine what it was like – that awful day in New York. I was just crazy with grief; so were the servants. And Colonel Arbuthnot was there too. He was John Armstrong’s best friend.”

“He saved my life in the War,” said Arbuthnot.

“We decided then and there (perhaps we were mad – I don’t know) that the sentence of death that Cassetti had escaped had got to be carried out. There were twelve of us – or rather eleven; Susanne’s father was over in France, of course. First we thought we’d draw lots as to who should do it, but in the end we decided on this way. It was the chauffeur, Antonio, who suggested it. Mary worked out all the details later with Hector MacQueen. He’d always adored Sonia – my daughter – and it was he who explained to us exactly how Cassetti’s money had managed to get him off.

“It took a long time to perfect our plan. We had first to track Ratchett down. Hardman managed that in the end. Then we had to try and get Masterman and Hector into his employment – or at any rate one of them. Well, we managed that. Then we had a consultation with Susanne’s father. Colonel Arbuthnot was very keen on having twelve of us. He seemed to think it made it more in order. He didn’t like the stabbing idea much, but he agreed that it did solve most of our difficulties. Well, Susanne’s father was willing. Susanne had been his only child. We knew from Hector that Ratchett would be coming back from the East sooner or later by the Orient Express. With Pierre Michel actually working on that train, the chance was too good to be missed. Besides, it would be a good way of not incriminating any outsiders.

“My daughter’s husband had to know, of course, and he insisted on coming on the train with her. Hector wangled it so that Ratchett selected the right day for travelling, when Michel would be on duty. We meant to engage every carriage in the Stamboul-Calais coach, but unfortunately there was one carriage we couldn’t get. It had been reserved long beforehand for a director of the company. ‘Mr. Harris,’ of course, was a myth. But it would have been awkward to have any stranger in Hector’s compartment. And then, at the last minute, you came…”

She stopped.

“Well,” she said, “you know everything now, M. Poirot. What are you going to do about it? If it must all come out, can’t you lay the blame upon me and me only? I would have stabbed that man twelve times willingly. It wasn’t only that he was responsible for my daughter’s death and her child’s and that of the other child who might have been alive and happy now. It was more than that: there had been other children kidnapped before Daisy, and there might be others in the future. Society had condemned him – we were only carrying out the sentence. But it’s unnecessary to bring all these others into it. All these good faithful souls – and poor Michel – and Mary and Colonel Arbuthnot – they love each other…”

Her voice was wonderful, echoing through the crowded space – that deep, emotional, heart-stirring voice that had thrilled many a New York audience.

Poirot looked at his friend.

“You are a director of the company, M. Bouc,” he said. “What do you say?”

M. Bouc cleared his throat.

“In my opinion, M. Poirot,” he said, “the first theory you put forward was the correct one – decidedly so. I suggest that that is the solution we offer to the Jugo-Slavian police when they arrive. You agree, doctor?”

“Certainly I agree,” said Dr. Constantine. “As regards the medical evidence, I think – er – that I made one or two fantastic suggestions.”

“Then,” said Poirot, “having placed my solution before you, I have the honour to retire from the case…”