Poirot jumped nearly out of his skin. His eyes positively bulged with astonishment.
"Why do you—what do you know of the Big Four, mademoiselle?"
"There is such an association, then! I overheard a reference to them, and asked my uncle about it afterwards. Never have I seen a man so afraid. He turned all white and shaking. He was in fear of them, monsieur, in great fear, I am sure of it. And, by mistake, they killed the American, Wilson."
"The Big Four," murmured Poirot. "Always the Big Four! An astonishing coincidence, mademoiselle, your uncle is still in danger. I must save him. Now recount to me exactly the events of that fatal evening. Show me the chess-board, the table, how the two men sat—everything."
She went to the side of the room and brought out a small table. The top of it was
