"It is all a long time ago, monsieur."
"Yes, yes. Nevertheless, it is there that we must seek."
He turned to leave the room, but paused with his hand on the door.
"Tell me, madame, do you ever remember your husband mentioning the phrase, 'The Big Four'?"
"The Big Four," she repeated thoughtfully. "No, I can't say I do."
6. THE WOMAN ON THE STAIRS
That was all that could be elicited from Mrs. Halliday. We hurried back to London, and the following day saw us en route for the Continent. With rather a rueful smile, Poirot observed:—-
"This Big Four, they make me to bestir myself, mon ami. I run up and down, all over the ground, like our old friend 'the human foxhound.'"
"Perhaps you'll meet him in Paris," I said, knowing that he referred to a certain Giraud, one of the most trusted detectives of the Sureté, whom he had met on a previous occasion.
Poirot made a grimace. "I devoutly hope not. He loved me not, that one."