A groan rose to my lips. I seized the pen. Perhaps by careful wording of the letter, I could convey a warning, and Poirot would be enabled to avoid the trap. It was the only hope.
But even that hope was not to remain. The Chinaman's voice rose, suave and courteous.
"Permit me to dictate to you."
He paused, consulted a sheaf of notes that lay by his side, and then dictated as follows:—
"Dear Poirot, I think I'm on the track of Number Four. A Chinaman came this afternoon and lured me down here with a bogus message. Luckily I saw through his little game in time, and gave him the slip. Then I turned the tables on him, and managed to do a bit of shadowing on my own account—rather neatly too, I flatter myself. I'm getting a bright young lad to carry this to you. Give him a half a crown, will you? That's what I promised him if it was delivered safely. I'm watching the house, and daren't leave. I shall wait for you until six o'clock, and if you haven't come then, I'll have a try at getting into the house on my own. It's too good a chance to miss, and, of course, the boy mightn't find you. But if he does, get him to bring you down here right away. And cover up those precious moustaches of yours in case any one's watching out from the house and might recognise you.
"Yours in haste,
"A. H."
Every word that I wrote plunged me deeper in despair. The thing was diabolically clever. I realised how closely every detail of our life must be known. It was just such an epistle as I might have penned myself. The acknowledgment that the Chinaman who had called that afternoon had endeavoured to "lure me away" discounted any good I might have done by leaving my "sign" of four books. It had been a trap, and I had seen through it, that was what Poirot would think. The time, too, was cleverly planned. Poirot, on receiving the note, would have just time to rush off with his innocent-looking guide, and that he would do so, I knew. My determination to make my way into the house would bring him post haste. He always displayed a ridiculous distrust of my capacities. He would be convinced that I was running into danger without being equal to the situation, and would rush down to take command of the situation.
But there was nothing to be done. I wrote as bidden. My captor took the note from me, read it, then nodded his head approvingly and handed it to one of the silent attendants who disappeared with it behind one of the silken hangings on the wall which masked a doorway.
With a smile the man opposite to me picked up a cable form and wrote. He handed it to me.
It read: "Release the white bird with all despatch."