"Outside the front door. They are cutting out the lock. When I give the word, not before, fall upon from him from behind and hold him fast. Be careful, he will have a knife." Presently there was a rending sound, and a little circle of light appeared through the door. It was extinguished immediately and then the door was slowly opened. Poirot and I flattened ourselves against the wall. I heard a man's breathing as he passed us. Then he flashed on his torch, and as he did so, Poirot hissed in my ear:

"Allez."

We sprang together, Poirot with a quick movement enveloped the intruder's head with a light woolen scarf whilst I pinioned his arms. The whole affair was quick and noiseless. I twisted a dagger from his hand, and as Poirot brought down the scarf from his eyes, whilst keeping it would tightly round his mouth, I jerked up my revolver where he could see it and understand that resistance was useless. As he ceased to struggle Poirot put his mouth close to his ear and began to whisper rapidly. After a minute the man nodded. Then enjoining silence with a movement of the hand, Poirot led the way out of the flat and down the stairs. Our captive followed, and I brought up the rear with the revolver. When we were out in the street, Poirot turned to me.

"There is a taxi waiting just round the corner. Give me the revolver. We shall not need it now."

"But if this fellow tries to escape?"

Poirot smiled.

"He will not."

I returned in a minute with the waiting taxi. The scarf had been unwound from the stranger's face, and I gave a start of surprise.

"He's not a Jap," I ejaculated in a whisper to Poirot.

"Observation was always your strong point, Hastings! Nothing escapes you. No, the man is not a Jap. He is an Italian."

We got into the taxi, and Poirot gave the driver an address in St John's Wood. I was by now completely fogged. I did not like to ask Poirot where we were going in front of our captive, and strove in vain to obtain some light upon the proceedings.

We alighted at the door of a small house standing back from the road. A returning wayfarer, slightly drunk, was lurching along the pavement and almost collided with Poirot, who said something sharply to him which I did not catch. All three of us went up the steps of the house. Poirot rang the bell and motioned us to stand a little aside. There was no answer and he rang again and then seized the knocker which he plied for some minutes vigorously.

A light appeared suddenly above the fanlight, and the door was opened cautiously a little way.

"What the devil do you want?" a man's voice demanded harshly.

"I want the doctor. My wife is taken ill."

"There's no doctor here."

The man prepared to shut the door, but Poirot thrust his foot in adroitly. He became suddenly a perfect caricature of an infuriated Frenchman.