—and had, as I found out afterwards, in reality been exactly one hour and twenty minutes—a faint scratching sound came to my ears. Poirot's hand touched mine. I rose, and together we moved carefully in the direction of the hall. The noise came from there. Poirot placed his lips to my ear.
"Outside the front door. They are cutting out the lock. When I give the word, not before, fall upon 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 woollen 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
