The gag prevented her from replying, but the murderous gleam in her eyes frightened me. I hoped devoutly that we should never fall into her power again.
Three minutes later we were outside the villa, and hurriedly traversing the garden. The road outside was deserted, and we were soon clear of the neighbourhood.
Then Poirot broke out.
"I deserve all that that woman said to me. I am a triple imbecile, a miserable animal, thirty-six times an idiot. I was proud of myself for not falling into their trap. And it was not even meant as a trap—except exactly in the way in which I fell into it. They knew I would see through it—they counted on my seeing through it. This explains all—the ease with which they surrendered Halliday—everything. Madame Olivier was the ruling spirit—-Vera Rossakoff only her lieutenant. Madame needed Halliday's ideas—she herself had the necessary genius to supply the gaps that perplexed him. Yes, Hastings, we know now who Number Three is—the woman who is probably the greatest scientist in the world! Think of it. The brain of the East, the science of the West—and two others whose identities we do not yet know. But we must find out. To-morrow we will return to London and set about it."
"You are not going to denounce Madame Olivier to the police?"
"I should not be believed. That woman is one of the idols of France. And we can prove nothing. We are lucky if she does not denounce us."
"What?"
"Think of it. We are found at night upon the premises with keys in our possession which she will swear she never gave us. She surprises us at the safe, and we gag and bind her and make away. Have no illusions, Hastings. The boot is not upon the right leg—is that how you say it?"
8. IN THE HOUSE OF THE ENEMY
After our adventure in the villa at Passy we returned post haste to London. Several letters were awaiting Poirot. He read one of them with a curious smile, and then handed it to me.