"Yes, the poison was meant for my uncle."
She had quite forgotten her first distrust now, and was speaking eagerly.
"Why do you say that, mademoiselle. Who should wish to poison Dr. Savaronoff?"
She shook her head.
"I do not know. I am all in the dark. And my uncle, he will not trust me. It is natural, perhaps. You see, he hardly knows me. He saw me as a child, and not since till I came to live with him here in London. But this much I do know, he is in fear of something. We have many secret societies in Russia, and one day I overheard something which made me think it was of just such a society he went in fear. Tell me, monsieur"—she came a step nearer, and dropped her voice—"have you ever heard of a society called the 'Big Four'?"
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 exquisite, inlaid with squares of silver and black to represent a chess-board.