There was a knock on the compartment door. M. Caux frowned. He opened it about six inches.
"What is the matter?" he said peremptorily. "I cannot be disturbed."
The egg-shaped head of Katherine's dinner acquaintance showed itself in the aperture. On his face was a beaming smile.
"My name," he said, "is Hercule Poirot."
"Not," the Commissary stammered, "not the Hercule Poirot?"
"The same," said Mr. Poirot. "I remember meeting you once, M. Caux, at the Sûreté in Paris, though doubtless you have forgotten me?"
“Not at all, Monsieur, not at all," declared the Commissary heartily. "But enter, I pray of you. You know of this"
"Yes, I know," said Hercule Poirot. "I came to see if I might be of any assistance?"
"We should be flattered," replied the Commissary promptly. "Let me present you, Mr. Poirot, to"—he consulted the passport he still held in his hand—"to Madame—er—Mademoiselle Grey."
Poirot smiled across at Katherine.
"It is strange, is it not," he murmured, "that my words should have come true so quickly?"
"Mademoiselle, alas! can tell us very little," said the Commissary.
"I have been explaining," said Katherine, "that this poor lady was a complete stranger to me."
Poirot nodded.
"But she talked to you, did she not?" he said gently.
"You formed an impression—is it not so?"
