“Ah, yes, the portmanteau call, as you say in England.”

Mary Debenham smiled a little in spite of herself. “Trunk call,” she corrected. “Yes, as you say, it is extremely annoying not to be able to get any word through, either by telephone or by telegraph.”

“And yet, Mademoiselle, this time your manner is quite different. You no longer betray the impatience. You are calm and philosophical.”

Mary Debenham flushed and bit her lip. She no longer felt inclined to smile.

“You do not answer, Mademoiselle?”

“I am sorry. I did not know that there was anything to answer.”

“Your change of attitude, Mademoiselle.”

“Don’t you think that you are making rather a fuss about nothing, M. Poirot?”

Poirot spread out his hands in an apologetic gesture.

“It is perhaps a fault with us detectives. We expect the behaviour to be always consistent. We do not allow for changes of mood.”

Mary Debenham made no reply.

“You know Colonel Arbuthnot well, Mademoiselle?”

He fancied that she was relieved by the change of subject.

“I met him for the first time on this journey.”

“Have you any reason to suspect that he may have known this man Ratchett?”

She shook her head decisively. “I am quite sure he didn’t.”

“Why are you sure?”

“By the way he spoke.”

“And yet, Mademoiselle, we found a pipe-cleaner on the floor of the dead man’s compartment. And Colonel Arbuthnot is the only man on the train who smokes a pipe.”

He watched her narrowly, but she displayed neither surprise nor emotion, merely said:

“Nonsense. It’s absurd. Colonel Arbuthnot is the last man in the world to be mixed up in a crime – especially a theatrical kind of crime like this.”

It was so much what Poirot himself thought that he found himself on the point of agreeing with her. He said instead:

“I must remind you that you do not know him very well, Mademoiselle.”

She shrugged her shoulders.

“I know the type well enough.”

He said very gently:

“You still refuse to tell me the meaning of those words: ‘When it’s behind us’?”

She replied coldly, “I have nothing more to say.”

“It does not matter,” said Hercule Poirot. “I shall find out.”

He bowed and left the compartment, closing the door after him.

“Was that wise, my friend?” asked M. Bouc. “You have put her on her guard – and through her, you have put the Colonel on his guard also.”

“Mon ami, if you wish to catch a rabbit you put a ferret into the hole, and if the rabbit is there – he runs. That is all I have done.”

They entered the compartment of Hildegarde Schmidt. The woman was standing in readiness, her face respectful but unemotional.

Poirot took a quick glance through the contents of the small case on the seat. Then he motioned to the attendant to get down the bigger suitcase from the rack.

“The keys?” he said.

“It is not locked, Monsieur.”

Poirot undid the hasps and lifted the lid.

“Aha!” he said, and turning to M. Bouc, “You remember what I said? Look here a little moment!”

On the top of the suitcase was a hastily rolled-up brown Wagon Lit uniform.

The stolidity of the German woman underwent a sudden change.

“Ach!” she cried. “That is not mine. I did not put it there. I have never looked in that case since we left Stamboul. Indeed, indeed, it is true!”

She looked from one to another of the men pleadingly.

Poirot took her gently by the arm and soothed her.

“No, no, all is well. We believe you. Do not be agitated. I am sure you did not hide the uniform there as I am sure that you are a good cook. See. You are a good cook, are you not?”

Bewildered, the woman smiled in spite of herself,

“Yes, indeed, all my ladies have said so. I —”

She stopped, her mouth open, looking frightened again.

“No, no,” said Poirot. “I assure you all is well. See, I will tell you how this happened. This man, the man you saw in Wagon Lit uniform, comes out of the dead man’s compartment. He collides with you. That is bad luck for him. He has hoped that no one will see him. What to do next? He must get rid of his uniform. It is now not a safeguard, but a danger.”

His glance went to M. Bow and Dr. Constantine, who were listening attentively.

“There is the snow, you see. The snow which confuses all his plans. Where can he hide these clothes? All the compartments are full. No, he passes one whose door is open, showing it to be unoccupied. It must be the one belonging to the woman with whom he has just collided. He slips in, removes the uniform and jams it hurriedly into a suitcase on the rack. It may be some time before it is discovered.”

“And then?” said M. Bouc.

“That we must discuss,” Poirot said with a warning glance.

He held up the tunic. A button, the third down, was missing. Poirot slipped his hand into the pocket and took out a conductor’s pass-key, used to unlock the doors of the compartments.

“Here is the explanation of how one man was able to pass through locked doors,” said M. Bouc. “Your questions to Mrs. Hubbard were unnecessary. Locked or not locked, the man could easily get through the communicating door. After all, if a Wagon Lit uniform, why not a Wagon Lit key?”

“Why not indeed?” returned Poirot.

“We might have known it, really. You remember that Michel said that the door into the corridor of Mrs. Hubbard’s compartment was locked when he came in answer to her bell.”

“That is so, Monsieur,” said the conductor. “That is why I thought the lady must have been dreaming.”

“But now it is easy,” continued M. Bouc. “Doubtless he meant to relock the communicating door, also, but perhaps he heard some movement from the bed and it startled him.”

“We have now,” said Poirot, “only to find the scarlet kimono.”

“True. And these last two compartments are occupied by men.”

“We will search all the same.”

“Oh! assuredly. Besides, I remember what you said.”

Hector MacQueen acquiesced willingly in the search.

“I’d just as soon you did,” he said with a rueful smile. “I feel I’m definitely the most suspicious character on the train. You’ve only got to find a will in which the old man left me all his money, and that’ll just about fix things.”

M. Bouc bent a suspicious glance upon him.

“That’s only my fun,” added MacQueen hastily. “He’d never have left me a cent, really. I was just useful to him – languages and so on. You’re likely to be out of luck, you know, if you don’t speak anything but good American. I’m no linguist myself, but I know what I call Shopping and Hotel – snappy bits in French and German and Italian.”

His voice was a little louder than usual. It was as though he were slightly uneasy over the search in spite of his expressed willingness.

Poirot emerged.

“Nothing,” he said. “Not even a compromising bequest!”

MacQueen sighed.

“Well, that’s a load off my mind,” he said humorously.

They moved on to the last compartment. The examination of the luggage of the big Italian and of the valet yielded no result.

The three men stood at the end of the coach looking at each other.