t the station in Paris。 That was clearly not part of the preconceived plan … you agree with me； Knighton？〃
The secretary started。 〃I beg your pardon； Mr Van Aldin。 I was not listening。〃
〃Day…dreaming； eh？〃 said Van Aldin。 〃That's not like you。 I believe that girl has bowled you over。〃
Knighton blushed。
〃She is a remarkably nice girl；〃 said Van Aldin thoughtfully； 〃very nice。 Did you happen to notice her eyes？〃
〃Any man；〃 said Knighton； 〃would be bound to notice her eyes。〃
Chapter 21
AT THE TENNIS
Several days had elapsed。 Katherine had been for a walk by herself one morning； and came back to find Lenox grinning at her expectantly。
〃Your young man has been ringing you up； Katherine！〃
〃Who do you call my young man？〃
〃A new one … Rufus Van Aldin's secretary。 You seem to have made rather an impression there。 You are being a serious breaker of hearts； Katherine。 First Derek Kettering； and now this young Knighton。 The funny thing is； that I remember him quite well。 He was in Mother's War Hospital that she ran out here。 I was only a kid of about eight at the time。〃
〃Was he badly wounded？〃
〃Shot in the leg； if I remember rightly … rather a nasty business。 I think the doctors messed it up a bit。 They said he wouldn't limp or anything； but when he left here he was still pletely dot and go one。〃
Lady Tamplin came out and joined them。
〃Have you been telling Katherine about Major Knighton？〃 she asked。 〃Such a dear fellow！ Just at first I didn't remember him … one had so many … but now it all es back。〃
〃He was a bit too unimportant to be remembered before；〃 said Lenox。 〃Now that he is a secretary to an American millionaire； it is a very different matter。〃
〃Darling！〃 said Lady Tamplin in her vague reproachful voice。
〃What did Major Knighton ring up about？〃 inquired Katherine。
〃He asked if you would like to go to the tennis this afternoon。 If so； he would call for you in a car。 Mother and I accepted for you with empressement。 Whilst you dally with a millionaire's secretary； you might give me a chance with the millionaire； Katherine。 He is about sixty； I suppose； so that he will be looking about for a nice sweet young thing like me。〃
〃I should like to meet Mr Van Aldin；〃 said Lady Tamplin earnestly； 〃one has heard so much of him。 Those fine rugged figures of the Western world …〃 she broke off … 〃so fascinating；〃 she murmured。
〃Major Knighton was very particular to say it was Mr Van Aldin's invitation；〃 said Lenox。 〃He said it so often that I began to smell a rat。 You and Knighton would make a very nice pair； Katherine。 Bless you； my children！〃
Katherine laughed； and went upstairs to change her clothes。
Knighton arrived soon after lunch and endured manfully Lady Tamplin's transports of recognition。
When they were driving together towards Cannes he remarked to Katherine： 〃Lady Tamplin has changed wonderfully little。〃
〃In manner or appearance？〃
〃Both。 She must be； I suppose； well over forty； but she is a remarkably beautiful woman still。〃
〃She is；〃 agreed Katherine。
〃I am very glad that you could e today；〃 went on Knighton。 〃M。 Poirot is going to be there also。 What an extraordinary little man he is。 Do you know him well； Miss Grey？〃
Katherine shook her head。 〃I met him on the train on the way here。 I was reading a detective novel； and I happened to say something about such things not happening in real life … of course； I had no idea of who he was。〃
〃He is a very remarkable person；〃 said Knighton slowly； 〃and has done some very remarkable things。 He has a kind of genius for going to the root of the matter； and right up to the end no one has any idea of what he is really thinking。 I remember I was staying at a house in Yorkshire； and Lady Clanravon's jewels were stolen。 It seemed at first to be a simple robbery； but it pletely baffled the local police。 I wanted them to call in Hercule Poirot； and said he was the only man who could help them； but they pinned their faith to Scotland Yard。〃
〃And what happened？〃 said Katherine curiously。
〃The jewels were never recovered；〃 said Knighton drily。
〃You really do believe in him？〃
〃I do indeed。 The te de la Roche is a pretty wily customer。 He has wriggled out of most things。 But I think he has met his match in Hercule Poirot。〃
〃The te de la Roche；〃 said Katherine thoughtfully； 〃so you really think he did it？〃
〃Of course。〃 Knighton looked at her in astonishment。 〃Don't you？〃
〃Oh yes；〃 said Katherine hastily； 〃that is； I mean； if it was not just an ordinary train robbery。〃
〃It might be； of course；〃 agreed the other； 〃but it seems to me that the te de la Roche fits into this business particularly well。〃
〃And yet he has an alibi。〃
〃Oh； alibis！〃 Knighton laughed； his face broke into his attractive boyish smile。
〃You confess that you read detective stories； Miss Grey。 You must know that anyone who has a perfect alibi is always open to grave suspicion。〃
〃Do you think that real life is like that？〃 asked Katherine； smiling。
〃Why not？ Fiction is founded on fact。〃
〃But is rather superior to it；〃 suggested Katherine。
〃Perhaps。 Anyway； if I was a criminal I should not like to have Hercule Poirot on my track。〃
〃No more should I；〃 said Katherine； and laughed。
They were met on arrival by Poirot。 As the day was warm he was attired in a white duck suit； with a white camellia in his buttonhole。
〃Bonjour； Mademoiselle；〃 said Poirot。 〃I look very English； do I not？〃
〃You look wonderful；〃 said Katherine tactfully。
〃You mock yourself at me；〃 said Poirot genially； 〃but no matter。 Papa Poirot； he always laughs the last。〃
〃Where is Mr Van Aldin？〃 asked Knighton。
〃He will meet us at our seats。 To tell you the truth； my friend； he is not too well pleased with me。 Oh； those Americans … the repose； the calm； they know it not！ Mr Van Aldin； he would that I fly myself in the pursuit of criminals through all the byways of Nice。〃
〃I should have thought myself that it would not have been a bad plan；〃 observed Knighton。
〃You are wrong；〃 said Poirot； 〃in these matters one needs not energy but finesse。 At the tennis one meets everyone。 That is so important。 Ah； there is Mr Kettering。〃
Derek came abruptly up to them。 He looked reckless and angry； as though something had arisen to upset him。 He and Knighton greeted each other with some frigidity。
Poirot alone seemed unconscious of a sense of strain； and chatted pleasantly in a laudable attempt to put everyone at their ease。 He paid little pliments。
〃It is amazing； M。 Kettering； how well you speak the French；〃 he observed … 〃so well that you could be taken for a Frenchman if you chose。 That is a very rare acplishment among Englishmen。〃
〃I wish I did；〃 said Katherine。 〃I am only too well aware that my French is of a painfully British order。〃
They reached their seats and sat down； and almost immediately Knighton perceived his employer signalling to him from the other end of the court； and went off to speak to him。
〃Me； I approve of that young man；〃 said Poirot； sending a beaming smile after the departing secretary； 〃and you； Mademoiselle？〃
〃I like him very much。〃
〃And you； M。 Kettering？〃
Some quick rejoinder was springing to Derek's lips； but he checked it as though something in the little Belgian's twinkling eyes had made him suddenly alert。 He spoke carefully； choosing his words。
〃Knighton is a very good fellow；〃 he said。 Just for a moment Katherine fancied that Poirot looked disappointed。
〃He is a great admirer of yours； M。 Poirot；〃 she said； and she related some of the things that Knighton had said。 It amused her to see the little man plume himself like a bird； thrusting out his chest； and assuming an air of mock modesty that would have deceived no one。
〃That reminds me； Mademoiselle；〃 he said suddenly； 〃I have a little matter of business I have to speak to you about。 When you were sitting talking to that poor lady in the train； I think you must have dropped a cigarette case。〃
Katherine looked rather astonished。 〃I don't think so；〃 she said。 Poirot drew from his pocket a cigarette case of soft blue leather； with the initial 〃K〃 on it in gold。
〃No； that is not mine；〃 Katherine said。
〃Ah； a thousand apologies。 It was doubtless Madame's own。 'K' of course； stands for Kettering。 We were doubtful； because she had another cigarette case in her bag； and it seemed odd that she should have two。〃
He turned to Derek suddenly。 〃You do not know； I suppose； whether this was your wife's case or not？〃
Derek seemed momentarily taken aback。 He stammered a little in his reply： 〃I … I don't know。 I suppose so。〃
〃It is not yours by any chance？〃
〃Certainly not。 If it were mine it would hardly have been in my wife's possession。〃
Poirot looked more ingenuous and childlike than ever。
〃I thought perhaps you might have dropped it when you were in your wife's partment；〃 he explained guilelessly。
〃I never was there。 I have already told the police that a dozen times。〃
〃A thousand pardons；〃 said Poirot； with his most apologetic air。 〃It was Mademoiselle here who mentioned having seen you going in。〃
He stopped with an air of embarrassment。
Katherine looked at Derek。 His face had gone rather white； but perhaps that was her fancy。 His laugh； when it came； was natural enough。
〃You made a mistake； Miss Grey；〃 he said easily。 〃From what the police have told me； I gather that my own partment was only a door or two away from that of my wife's … though I never suspected the fact at the time。 You must have seen me going into my own partment。〃 He got up quickly as he saw Van Aldin and Knighton approaching。
〃I'm going to leave you now；〃 he announced。 〃I can't stand my father…in…law at any price。〃
Van Aldin greeted Katherine very courteously； but was clearly in a bad humour。
〃You seem fond of watching tennis； M。 Poirot；〃 he growled。
〃It is a pleasure to me； yes；〃 cried Poirot placidly。
〃It is as well you are in France；〃 said Van Aldin。 〃We are made of sterner stuff in the States。 Business es before pleasure there。〃
Poirot did not take offence； indeed； he smiled gently and confidingly at the irate millionaire。
〃Do no