1Several days had elapsed. Katherine had been for a walk by herself one morning, and came back to find Lenox grinning at her expectantly.

2"Your young man has been ringing you up, Katherine!"

3"Who do you call my young man?"

4"A new one—Rufus Van Aldin's secretary. You seem to have made rather an impression there. You are becoming 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."

5"Was he badly wounded?"

6"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 completely dot and go one."

7Lady Tamplin came out and joined them.

8"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 comes back."

9"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."

10"Darling!" said Lady Tamplin in her vague reproachful voice.

11"What did Major Knighton ring up about?" inquired Katherine.

12"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."

13"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.

14"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!"

15Katherine laughed, and went upstairs to change her clothes.

16Knighton arrived soon after lunch and endured manfully Lady Tamplin's transports of recognition.

17When they were driving together towards Cannes he remarked to Katherine: "Lady Tamplin has changed wonderfully little."

18"In manner or appearance?"

19"Both. She must be, I suppose, well over forty, but she is a remarkably beautiful woman still."

20"She is," agreed Katherine.

21"I am very glad that you could come to-day," 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?"

22Katherine 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."

23"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 completely 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."

24"And what happened?" said Katherine curiously.

25"The jewels were never recovered," said Knighton drily.

26"You really do believe in him?"

27"I do indeed. The Comte 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."

28"The Comte de la Roche," said Katherine thoughtfully; "so you really think he did it?"

29"Of course." Knighton looked at her in astonishment. "Don't you?"

30"Oh yes," said Katherine hastily; "that is, I mean, if it was not just an ordinary train robbery."

31"It might be, of course," agreed the other, "but it seems to me that the Comte de la Roche fits into this business particularly well."

32"And yet he has an alibi."

33"Oh, alibis!" Knighton laughed, his face broke into his attractive boyish smile.

34"You confess that you read detective stories, Miss Grey. You must know that any one who has a perfect alibi is always open to grave suspicion."

35"Do you think that real life is like that?" asked Katherine, smiling.

36"Why not? Fiction is founded on fact."

37"But is rather superior to it," suggested Katherine.

38"Perhaps. Anyway, if I was a criminal I should not like to have Hercule Poirot on my track."

39"No more should I," said Katherine, and laughed.

40They 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.

41"Bon jour, Mademoiselle," said Poirot. "I look very English, do I not?"

42"You look wonderful," said Katherine tactfully.

43"You mock yourself at me," said Poirot genially, "but no matter. Papa Poirot, he always laughs the last."

44"Where is Mr. Van Aldin?" asked Knighton.

45"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."

46"I should have thought myself that it would not have been a bad plan," observed Knighton.

47"You are wrong," said Poirot; "in these matters one needs not energy but finesse. At the tennis one meets every one. That is so important. Ah, there is Mr. Kettering."

48Derek 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 any sense of strain, and chatted pleasantly in a laudable attempt to put every one at his ease. He paid little compliments.

49"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 accomplishment among Englishmen."

50"I wish I did," said Katherine. "I am only too well aware that my French is of a painfully British order."

51They reached their seats and sat down, and almost immediately Knighton perceived his employer signaling to him from the other end of the court, and went off to speak to him.

52"Me, I approve of that young man," said Poirot, sending a beaming smile after the departing secretary; "and you, Mademoiselle?"

53"I like him very much."

54"And you, M. Kettering?"

55Some 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.

56"Knighton is a very good fellow," he said.

57Just for a moment Katherine fancied that Poirot looked disappointed.

58"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.

59"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."

60Katherine 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.

61"No, that is not mine," Katherine said.

62"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?"

63Derek seemed momentarily taken aback. He stammered a little in his reply: "I—I don't know. I suppose so."

64"It is not yours by any chance?"

65"Certainly not. If it were mine it would hardly have been in my wife's possession."

66Poirot looked more ingenuous and childlike than ever.

67"I thought perhaps you might have dropped it when you were in your wife's compartment," he explained guilelessly.

68"I never was there. I have already told the police that a dozen times."

69"A thousand pardons," said Poirot, with his most apologetic air. "It was Mademoiselle here who mentioned having seen you going in."

70He stopped with an air of embarrassment.

71Katherine looked at Derek. His face had gone rather white, but perhaps that was her fancy. His laugh, when it came, was natural enough.

72"You made a mistake, Miss Grey," he said easily. "From what the police have told me, I gather that my own compartment 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 compartment." He got up quickly as he saw Van Aldin and Knighton approaching.

73"I'm going to leave you now," he announced. "I can't stand my father-in-law at any price."

74Van Aldin greeted Katherine very courteously, but was clearly in a bad humour.

75"You seem fond of watching tennis, M. Poirot," he growled.

76"It is a pleasure to me, yes," cried Poirot placidly.

77"It is as well you are in France," said Van Aldin. "We are made of sterner stuff in the States. Business comes before pleasure there."

78Poirot did not take offence; indeed, he smiled gently and confidingly at the irate millionaire.

79"Do not enrage yourself, I beg of you. Every one has his own methods. Me, I have always found it a delightful and pleasing idea to combine business and pleasure together."

80He glanced at the other two. They were deep in conversation, absorbed in each other. Poirot nodded his head in satisfaction, and then leant towards the millionaire, lowering his voice as he did so.

81"It is not only for pleasure that I am here, M. Van Aldin. Observe just opposite us that tall old man—the one with the yellow face and the venerable beard."

82"Well, what of him?"

83"That," Poirot said, "is M. Papopolous."

84"A Greek, eh?"

85"As you say—a Greek. He is a dealer in antiques of world-wide reputation. He has a small shop in Paris, and he is suspected by the police of being something more."

86"What?"

87"A receiver of stolen goods, especially jewels. There is nothing as to the re-cutting and re-setting of gems that he does not know. He deals with the highest in Europe and with the lowest of the riff-raff of the underworld."

88Van Aldin was looking at Poirot with suddenly awakened attention.

89"Well?" he demanded, a new note in his voice.

90"I ask myself," said Poirot, "I, Hercule Poirot"—he thumped himself dramatically on the chest—"ask myself why is M. Papopolous suddenly come to Nice?"

91Van Aldin was impressed. For a moment he had doubted Poirot and suspected the little man of being past his job, a poseur only. Now, in a moment, he switched back to his original opinion. He looked straight at the little detective.

92"I must apologize to you, M. Poirot."

93Poirot waved the apology aside with an extravagant gesture.

94"Bah!" he cried, "all that is of no importance. Now listen, M. Van Aldin; I have news for you."

95The millionaire looked sharply at him, all his interest aroused.

96Poirot nodded.

97"It is as I say. You will be interested. As you know, M. Van Aldin, the Comte de la Roche has been under surveillance ever since his interview with the Juge d'Instruction. The day after that, during his absence, the Villa Marina was searched by the police."

98"Well," said Van Aldin, "did they find anything? I bet they didn't."

99Poirot made him a little bow.

100"Your acumen is not at fault, M. Van Aldin. They found nothing of an incriminating nature. It was not to be expected that they would. The Comte de la Roche, as your expressive idiom has it, was not born on the preceding day. He is an astute gentleman with great experience."

101"Well, go on," growled Van Aldin.

102"It may be, of course, that the Comte had nothing of a compromising nature to conceal. But we must not neglect the possibility. If, then, he has something to conceal, where is it? Not in his house—the police searched thoroughly. Not on his person, for he knows that he is liable to arrest at any minute. There remains—his car. As I say, he was under surveillance. He was followed on that day to Monte Carlo. From there he went by road to Mentone, driving himself. His car is a very powerful one, it outdistanced his pursuers, and for about a quarter of an hour they completely lost sight of him."

103"And during that time you think he concealed something by the roadside?" asked Van Aldin, keenly interested.

104"By the roadside, no. Ça n'est pas pratique. But listen now—me, I have made a little suggestion to M. Carrège. He is graciously pleased to approve of it. In each Bureau de Poste in the neighbourhood it has been seen to that there is some one who knows the Comte de la Roche by sight. Because, you see, Monsieur, the best way of hiding a thing is by sending it away by the post."

105"Well?" demanded Van Aldin; his face was keenly alight with interest and expectation.

106"Well—voilà!" With a dramatic flourish Poirot drew out from his pocket a loosely wrapped brown paper package from which the string had been removed.

107"During that quarter of an hour's interval, our good gentleman mailed this."

108"The address?" asked the other sharply.

109Poirot nodded his head.

110"Might have told us something, but unfortunately it does not. The package was addressed to one of these little newspaper shops in Paris where letters and parcels are kept until called for on payment of a small commission."

111"Yes, but what is inside?" demanded Van Aldin impatiently.

112Poirot unwrapped the brown paper and disclosed a square cardboard box. He looked round him.

113"It is a good moment," he said quietly. "All eyes are on the tennis. Look, Monsieur!"

114He lifted the lid of the box for the fraction of a second. An exclamation of utter astonishment came from the millionaire. His face turned as white as chalk.

115"My God!" he breathed, "the rubies."

116He sat for a minute as though dazed. Poirot restored the box to his pocket and beamed placidly. Then suddenly the millionaire seemed to come out of his trance; he leaned across to Poirot and wrung his hand so heartily that the little man winced with pain.

117"This is great," said Van Aldin. "Great! You are the goods, M. Poirot. Once and for all, you are the goods."

118"It is nothing," said Poirot modestly. "Order, method, being prepared for eventualities beforehand—that is all there is to it."

119"And now, I suppose, the Comte de la Roche has been arrested?" continued Van Aldin eagerly.

120"No," said Poirot.

121A look of utter astonishment came over Van Aldin's face.

122"But why? What more do you want?"

123"The Comte's alibi is still unshaken."

124"But that is nonsense."

125"Yes," said Poirot; "I rather think it is nonsense, but unfortunately we have to prove it so."

126"In the meantime he will slip through your fingers."

127Poirot shook his head very energetically.

128"No," he said, "he will not do that. The one thing the Comte cannot afford to sacrifice is his social position. At all costs he must stop and brazen it out."

129Van Aldin was still dissatisfied.

130"But I don't see—"

131Poirot raised a hand. "Grant me a little moment, Monsieur. Me, I have a little idea. Many people have mocked themselves at the little ideas of Hercule Poirot—and they have been wrong."

132"Well," said Van Aldin, "go ahead. What is this little idea?"

133Poirot paused for a moment and then he said:

134"I will call upon you at your hotel at eleven o'clock to-morrow morning. Until then, say nothing to any one."