Lady Yardly had turned away. She still held the telegram in her hand.
'I wish you wouldn't sell it, George,' she said, in a low voice. 'It's been in the family so long.' She waited, as though for a reply, but when none came her face hardened. She shrugged her shoulders, 'I must go and dress. I suppose I had better display "the goods".' She turned to Poirot with a slight grimace. 'It's one of the most hideous necklaces that was ever designed! George has always promised to have the stones reset for me, but it's never been done.'
She left the room.
Half an hour later, we three were assembled in the great drawingroom awaiting the lady. It was already a few minutes past the dinner hour.
Suddenly there was a low rustle, and Lady Yardly appeared framed in the doorway, a radiant figure in a long white shimmering dress.
Round the column of her neck was a rivulet of fire. She stood there with one hand just touching the necklace.
'Behold the sacrifice,' she said gaily. Her ill-humour seemed to have vanished. 'Wait while I turn the big light on and you shall feast your eyes on the ugliest necklace in England.'
The switches were just outside the door. As she stretched out her hand to them, the incredible thing happened. Suddenly without any warning, every light was extinguished, the door banged, and from the other side of it came a long-drawn piercing woman's scream.
'My God!' cried Lord Yardly. 'That was Maude's voice! What has happened?'
We rushed blindly for the door, cannoning into each other in the darkness. It was some minutes before we could find it. What a sight met our eyes! Lady Yardly lay senseless on the marble floor, a crimson mark on her white throat where the necklace had been wrenched from her neck.
As we bent over her, uncertain for the moment whether she was dead or alive, her eyelids opened.
'The Chinaman,' she whispered painfully. 'The Chinaman - the side door.'
Lord Yardly sprang up with an oath. I accompanied him, my heart beating wildly. The Chinaman again! The side door in question was a small one in the angle of the wall, not more than a dozen yards from the scene of the tragedy. As we reached it, I gave a cry. There, just short of the threshold, lay the guttering necklace, evidently dropped by the thief in the panic of his flight. I swooped joyously down on it. Then I uttered another cry which Lord Yardly echoed.
For in the middle of the necklace was a great gap. The Star of the East was missing!
'That settles it,' I breathed. 'These were no ordinary thieves. This one stone was all they wanted.'
'But how did the fellow get in?'
'Through this door.'
'But it's always locked.'
I shook my head. 'It's not locked now. See.' I pulled it open as I spoke.
As I did so something fluttered to the ground. I picked it up. It was a piece of silk, and the embroidery was unmistakable. It had been torn from a Chinaman's robe.
'In his haste it caught in the door,' I explained. 'Come, hurry. He cannot have gone far as yet.'
But in vain we bunted and searched. In the pitch darkness of the night, the thief had found it easy to make his getaway. We returned reluctantly, and Lord Yardly sent off one of the footmen post-haste to fetch the police.
Lady Yardly, aptly ministered to by Poirot, who is as good as a woman in these matters, was sufficiently recovered to be able to tell her story.
'I was just going to turn on the other light,' she said, 'when a man sprang on me from behind. He tore my necklace from my neck with such force that I fell headlong to the floor. As I fell I saw him disappearing through the side door. Then I realized by the pigtail and the embroidered robe that he was a Chinaman.' She stopped with a shudder.
The butler reappeared. He spoke in a low voice to Lord Yardly.
'A gentleman from Mr Hoffberg's, m'lord. He says you expect him.'
'Good heavens!' cried the distracted nobleman. 'I must see him, I suppose. No, not here, Mullings, in the library.'
I drew Poirot aside.
'Look here, my dear fellow, hadn't we better get back to London?'
'You think so, Hastings? Why?'
'Well' - I coughed delicately - 'things haven't gone very well, have they? I mean, you tell Lord Yardly to place himself in your hands and all will be well - and then the diamond vanishes from under your very nose!'
'True,' said Poirot, rather crestfallen. 'It was not one of my most striking triumphs.'
This way of describing events almost caused me to smile, but I stuck to my guns.
'So, having - pardon the expression - rather made a mess of things, don't you think it would be more graceful to leave immediately?'
'And the dinner, the without doubt excellent dinner, that the chef of Lord Yardly has prepared? '
'Oh, what's dinner!' I said impatiently.
Poirot held up his hands in horror.
'Mon Dieu! It is that in this country you treat the affairs gastronomic with a criminal indifference.'
'There's another reason why we should get back to London as soon as possible,' I continued.
'What is that, my friend?'
'The other diamond,' I said, lowering my voice. 'Miss Marvell's.'
'Eh bien, what of it?'
'Don't you see?' His unusual obtuseness annoyed me. What had happened to his usually keen wits? 'They've got one, now they'll go for the other.'
'Tiens!' cried Poirot, stepping back a pace and regarding me with admiration. 'But your brain marches to a marvel, my friend! Figure to yourself that for the moment I had not thought of that! But there is plenty of time. The full of the moon, it is not until Friday.'
I shook my head dubiously. The full of the moon theory left me entirely cold. I had my way with Poirot, however, and we departed immediately, leaving behind us a note of explanation and apology for Lord Yardly.
My idea was to go at once to the Magnificent, and relate to Miss Marvell what had occurred, but Poirot vetoed the plan, and insisted that the morning would be time enough. I gave in rather grudgingly.
In the morning Poirot seemed strangely disinclined to stir out. I began to suspect that, having made a mistake to start with, he was singularly loath to proceed with the case. In answer to my persuasions, he pointed out, with admirable common sense, that as the details of the affair at Yardly Chase were already in the morning papers the Rolfs would know quite as much as we could tell them. I gave way unwillingly.
Events proved my forebodings to be justified. About two o'clock, the telephone rang. Poirot answered it. He listened for some moments, then with a brief 'Bien, j'y serai' he rang off, and turned to me.
'What do you think, mon ami?' He looked half ashamed, half excited.
'The diamond of Miss Marvell, it has been stolen.'
'What?' I cried, springing up. 'And what about the 'full of the moon' now?' Poirot hung his head. When did this happen?'
'This morning, I understand.'
I shook my head sadly. 'If only you had listened to me. You see I was right.'
'It appears so, mon ami' said Poirot cautiously. 'Appearances are deceptive, they say, but it certainly appears so.'
As we hurried in a taxi to the Magnificent, I puzzled out the true inwardness of the scheme.
'That "full of the moon" idea was clever. The whole point of it was to get us to concentrate on the Friday, and so be off our guard beforehand. It is a pity you did not realize that.'
'Ma foi!' said Poirot airily, his nonchalance quite restored after its brief eclipse. 'One cannot think of everything!'
I felt sorry for him. He did so hate failure of any kind.
'Cheer up,' I said consolingly. 'Better luck next time.'
At the Magnificent, we were ushered at once into the manager's office. Gregory Rolf was there with two men from Scotland Yard. A pale-faced clerk sat opposite them.
Rolf nodded to us as we entered.
'We're getting to the bottom of it,' he said. 'But it's almost unbelievable. How the guy had the nerve I can't think.'