With a word of excuse to Lady Tamplin； he broke it open； and an expression of utter astonishment came over his face as he read； then he looked at his hostess。
〃This is most extraordinary。 I say； Rosalie； I am afraid I will have to leave you。 The Prefect of Police wants to see me at once。 I can't think what about。〃
〃Your sins have found you out；〃 remarked Lenox。
〃They must have；〃 said Derek； 〃probably some idiotic nonsense； but I suppose I shall have to push off to the Prefecture。 How dare the old boy rout me out from dinner？ It ought to be something deadly serious to justify that；〃 and he laughed as he pushed back his chair and rose to leave the room。
Chapter 13
VAN ALDIN GETS A TELEGRAM
On the afternoon of the 15th February a thick yellow fog had settled down on London。
Rufus Van Aldin was in his suite at the Savoy and was making the most of the atmospheric conditions by working double time。 Knighton was overjoyed。 He had found it difficult of late to get his employer to concentrate on the matters in hand。 When he had ventured to urge certain courses； Van Aldin had put him off with a curt word。 But now Van Aldin seemed to be throwing himself into work with redoubled energy； and the secretary made the most of his opportunities。 Always tactful； he plied the spur so unobtrusively that Van Aldin never suspected it。
Yet in the middle of this absorption in business matters； one little fact lay at the back of Van Aldin's mind。 A chance remark of Knighton's； uttered by the secretary in all unconsciousness； had given rise to it。 It now festered unseen； gradually reaching further and further forward into Van Aldin's consciousness； until at last； in spite of himself he had to yield to its insistence。
He listened to what Knighton was saying with his usual air of keen attention； but in reality not one word of it perated his mind。 He nodded automatically； however； and the secretary turned to some other paper。
As he was sorting them out； his employer spoke：
〃Do you mind telling me that over again； Knighton？〃
For a moment Knighton was at a loss。
〃You mean about this； sir？〃 He held up a closely written pany report。
〃No； no；〃 said Van Aldin； 〃what you told me about seeing Ruth's maid in Paris last night。 I can't make it out。 You must have been mistaken。〃
〃I can't have been mistaken； sir； I actually spoke to her。〃
〃Well； tell me the whole thing again。〃
Knighton plied。
〃I had fixed up the deal with Barthermers；〃 he explained； 〃and had gone back to the Ritz to pick up my traps preparatory to having dinner and catching the nine o'clock train from the Gare du Nord。 At the reception desk I sars Kettering's maid。 I went up to her and asked if Mrs Kettering was staying there。〃
〃Yes； yes；〃 said Van Aldin。 〃Of course。 Naturally。 And she told you that Ruth had gone on to the Riviera and had sent her to the Ritz to await further orders there？〃
〃Exactly that； sir。〃
〃It is very odd；〃 said Van Aldin。 〃Very odd； indeed； unless the woman had been impertinent or something of that kind。〃
〃In that case；〃 objected Knighton； 〃surely Mrs Kettering would have paid her down a sum of money； and told her to go back to England。 She would hardly have sent her to the Ritz。〃
〃No；〃 muttered the millionaire； 〃that's true。〃
He was about to say something further； but checked himself。 He was fond of Knighton and liked and trusted him； but he could hardly discuss his daughter's private affairs with his secretary。 He had already felt hurt by Ruth's lack of frankness； and this chance revelation which had e to him did nothing to allay his misgivings。
Why had Ruth got rid of her maid in Paris？ What possible object or motive could she have had in so doing？
He reflected for a moment or two on the curious bination of chance。 How should it have occurred to Ruth； except as the wildest coincidence； that the first person that the maid should run across in Paris should be her father's secretary？ Ah； but that was the way things happened。 That was the way things got found out。
He winced at the last phrase； it had arisen with plete naturalness to his mind。 Was there then 'something to be found out'？ He hated to put this question to himself； he had no doubt of the answer。 The answer was … he was sure of it … Armand de la Roche。
It was bitter to Van Aldin that a daughter of his should be gulled by such a man； yet he was forced to admit that she was in good pany … that other well…bred and intelligent women had succumbed just as easily to the Count's fascination。 Men saw through him； women did not。
He sought now for a phrase that would allay any suspicion that his secretary might have felt。
〃Ruth is always changing her mind about things at a moment's notice；〃 he remarked； and then he added in a would…be careless tone； 〃The maid didn't give any … er … reason for this change of plan？〃
Knighton was careful to make his voice as natural as possible as he replied：
〃She said； sir； that Mrs Kettering had met a friend unexpectedly。〃
〃Is that so？〃
The secretary's practised ears caught the note of strain underlying the seemingly casual tone。
〃Oh； I see。 Man or woman？〃
〃I think she said a man； sir。〃
Van Aldin nodded。 His worst fears were being realized。 He rose from his chair； and began pacing up and down the room； a habit of his when agitated。 Unable to contain his feelings any longer； he burst forth：
〃There is one thing no man can do； and that is to get a woman to listen to reason。 Somehow or other； they don't seem to have any kind of sense。 Talk of woman's instinct … why； it is well known all the world over that a woman is the surest mark for any rascally swindler。 Not one in ten of them knows a scoundrel when she meets one； they can be preyed on by any good…looking fellow with a soft side to his tongue。 If I had my way …〃
He was interrupted。 A page…boy entered with a telegram。 Van Aldin tore it open； and his face went a sudden chalky white。 He caught hold of the back of a chair to steady himself； and waved the page…boy from the room。
〃What's the matter； sir？〃
Knighton had risen in concern。
〃Ruth！〃 said Van Aldin hoarsely。
〃Mrs Kettering？〃
〃Killed！〃
〃An accident to the train？〃
Van Aldin shook his head。
〃No。 From this it seems she has been robbed as well。 They don't use the word； Knighton； but my poor girl has been murdered。〃
〃Oh； my God； sir！〃
Van Aldin tapped the telegram with his forefinger。
〃This is from the police at Nice。 I must go out there by the first train。〃
Knighton was efficient as ever。 He glanced at the clock。
〃Five o'clock from Victoria； sir。〃
〃That's right。 You will e with me； Knighton。 Tell my man； Archer； and pack your own things。 See to everything here。 I want to go round to Curzon Street。〃
The telephone rang sharply； and the secretary tilted the receiver。
〃Yes； who is it？〃
Then to Van Aldin。
〃Mr Goby； sir。〃
〃Goby？ I can't see him now。 No … wait； we have plenty of time。 Tell them to send him up。〃
Van Aldin was a strong man。 Already he had recovered that iron calm of his。 Few people would have noticed anything amiss in his greeting to Mr Goby。
〃I am pressed for time； Goby。 Got anything important to tell me？〃
Mr Goby coughed。
〃The movements of Mr Kettering； sir。 You wished them reported to you。〃
〃Yes … well？〃
〃Mr Kettering； sir； left London for the Riviera yesterday morning。〃
〃What？〃
Something in his voice must have startled Mr Goby。 That worthy gentleman departed from his usual practice of never looking at a person to whom he was talking； and stole a fleeting glance at the millionaire。
〃What train did he go on？〃 demanded Van Aldin。
〃The Blue Train； sir。〃
Mr Goby coughed again and spoke to the clock on the mantelpiece。
〃Mademoiselle Mirelle； the dancer from the Parthenon； went by the same train。〃
Chapter 14
ADA MASON'S STORY
〃I cannot repeat to you often enough； Monsieur； our horror； our consternation； and the deep sympathy we feel for you。〃
Thus M。 Carrege； the Juge d'Instruction； addressed Van Aldin。 M。 Caux； the missary； made sympathetic noises in his throat。 Van Aldin brushed away horror； consternation and sympathy with an abrupt gesture。 The scene was the Examining Magistrate's room at Nice。 Besides M。 Carrege； the missary； and Van Aldin； there was a further person in the room。 It was that person who now spoke。
〃M。 Van Aldin；〃 he said； 〃desires action … swift action。〃
〃Ah！〃 cried the missary； 〃I have not yet presented you。 M。 Van Aldin； this is M。 Hercule Poirot； you have doubtless heard of him。 Although he has retired from his profession for some years now； his name is still a household word as one of the greatest living detectives。〃
〃Pleased to meet you； M。 Poirot；〃 said Van Aldin； falling back mechanically on a formula that he had discarded some years ago。 〃You have retired from your profession？〃
〃That is so； Monsieur。 Now I enjoy the world。〃
The little man made a grandiloquent gesture。
〃M。 Poirot happened to be travelling on the Blue Train；〃 explained the missary； 〃and he has been so kind as to assist us out of his vast experience。〃
The millionaire looked at Poirot keenly。 Then he said unexpectedly：
〃I am a very rich man； M。 Poirot。 It is usually said that a rich man labours under the belief that he can buy everything and everyone。 That is not true。 I am a big man in my way； and one big man can ask a favour from another big man。〃
Poirot nodded a quick appreciation。
〃That is very well said； M。 Van Aldin。 I place myself entirely at your service。〃
〃Thank you；〃 said Van Aldin。 〃I can only say： call upon me at any time； and you will not find me ungrateful。 And now； gentlemen； to business。〃
〃I propose；〃 said M。 Carrege； 〃to interrogate the maid； Ada Mason。 You have her here； I understand？〃
〃Yes；〃 said Van Aldin。 〃We picked her up in Paris in passing through。 She was very upset to hear of her mistress's death； but she tells her story coherently enough。〃
〃We will have her in； then；〃 said M。 Carrege。
He rang the bell on his desk； and in a few minutes Ada Mason entered the room。
She was very neatly dressed in black； and the tip of her nose was red。 She had exchanged her grey travelling gloves for a pair of black suede ones。 She cast a look round the Examining Magistrate's office in some trepidation； and seemed relieved at the presence of her mistress's father。 The Examining Magistrate prided himself on his geniality of manner； and did his best to put her at her ease。 He was helped in this by Poirot； who acted as interpreter； and whose friendly manner was reassuring to the Englishman。
〃Your name is Ada Mason； is that right？〃
〃Ada Beatrice I was christened； sir；〃 said Mason primly。
〃Just so。 And we can understand； Mason； that this has all been very distressing。〃
〃Oh； indeed it has； sir。 I have been with many ladies and always given satisfaction； I hope； and I never dreamt of anything of this kind happening in any situation where I was。〃
〃No； no；〃 said M。 Carrege。
〃Naturally I have read of such things； of course； in the Sunday papers。 And then I always have understood that those foreign trains …〃 She suddenly checked her flow； remembering th