Tarling walked out of Scotland Yard on to the sunlit Embankment, trouble in his face. He told himself that the case was getting beyond him and that it was only the case and its development which worried him. The queer little look which had dawned on the Commissioner's face when he learnt that the heir to the murdered Thornton Lyne's fortune was the detective who was investigating his murder, and that Tarling's revolver had been found in the room where the murder had been committed, aroused nothing but an inward chuckle.

That suspicion should attach to him was, he told himself, poetic justice, for in his day he himself had suspected many men, innocent or partly innocent.

He walked up the stairs to his room and found Ling Chu polishing the meagre stock of silver which Tarling possessed. Ling Chu was a thief-catcher and a great detective, but he had also taken upon himself the business of attending to Tarling's personal comfort. The detective spoke no word, out went straight to the cupboard where he kept his foreign kit. On a shelf in neat array and carefully folded, were the thin white drill suits he wore in the tropics. His sun helmet hung on a peg, and on the opposite wall was a revolver holster hanging by a strap. He lifted the holster. It was empty. He had had no doubts in his mind that the holster would be empty and closed the door with a troubled frown.

"Ling Chu," he said quietly.

"You speak me, Lieh Jen?" said the man, putting down the spoons and rubber he was handling.

"Where is my revolver?"

"It is gone, Lieh Jen," said the man calmly.

"How long has it been gone?"

"I miss him four days," said Ling Chu calmly;

"Who took it?" demanded Tarling.

"I miss him four days," said the man.

There was an interval of silence, and Tarling nodded his head slowly.

"Very good, Ling Chu," he said, "there is no more to be said."

For all his outward calm, he was distressed in mind.

Was it possible that anybody could have got into the room in Ling Chu's absence--he could only remember one occasion when they had been out together, and that was the night he had gone to the girl's flat and Ling Chu had shadowed him.

What if Ling Chu----?

He dismissed the thought as palpably absurd. What interest could Ling Chu have in the death of Lyne, whom he had only seen once, the day that Thornton Lyne had called Tarling into consultation at the Stores?

That thought was too fantastic to entertain, but nevertheless it recurred again and again to him and in the end he sent his servant away with a message to Scotland Yard, determined to give even his most fantastic theory as thorough and impartial an examination as was possible.

The flat consisted of four rooms and a kitchen. There was Tarling's bedroom communicating with his dining and sitting-room. There was a spare-room in which he kept his boxes and trunks--it was in this room that the revolver had been put aside--and there was the small room occupied by Ling Chu. He gave his attendant time to get out of the house and well on his journey before he rose from the deep chair where he had been sitting in puzzled thought and began his inspection.

Ling Chu's room was small and scrupulously clean. Save for the bed and a plain black-painted box beneath the bed, there was no furniture. The well-scrubbed boards were covered with a strip of Chinese matting and the only ornamentation in the room was supplied by a tiny red lacquer vase which stood on the mantelpiece.

Tarling went back to the outer door of the flat and locked it before continuing his search. If there was any clue to the mystery of the stolen revolver it would be found here, in this black box. A Chinaman keeps all his possessions "within six sides," as the saying goes, and certainly the box was very well secured. It was ten minutes before he managed to find a key to shift the two locks with which it was fastened.

The contents of the box were few. Ling Chu's wardrobe was not an extensive one and did little more than half fill the receptacle. Very carefully he lifted out the one suit of clothes, the silk shirts, the slippers and the odds and ends of the Chinaman's toilet and came quickly to the lower layer. Here he discovered two lacquer boxes, neither of which were locked or fastened.

The first of these contained sewing material, the second a small package wrapped in native paper and carefully tied about with ribbon. Tarling undid the ribbon, opened the package and found to his surprise a small pad of newspaper cuttings. In the main they were cuttings from colloquial journals printed in Chinese characters, but there were one or two paragraphs evidently cut from one of the English papers published in Shanghai.

He thought at first that these were records of cases in which Ling Chu had been engaged, and though he was surprised that the Chinaman should have taken the trouble to collect these souvenirs--especially the English cuttings--he did not think at first that there was any significance in the act. He was looking for some clue--what he knew not--which would enable him to explain to his own satisfaction the mystery of the filched pistol.

He read the first of the European cuttings idly, but presently his eyes opened wide.

"There was a fracas at Ho Hans's tea-room last night, due apparently to the too-persistent attentions paid by an English visitor to the dancing girl, the little Narcissus, who is known to the English, or such as frequent Ho Hans's rooms, as The Little Daffodil----"

He gasped. The Little Daffodil! He let the cutting drop on his knee and frowned in an effort of memory. He knew Shanghai well. He knew its mysterious under-world and had more than a passing acquaintance with Ho Hans's tea-rooms. Ho Hans's tea-room was, in fact, the mask which hid an opium den that he had been instrumental in cleaning up just before he departed from China. And he distinctly remembered the Little Daffodil. He had had no dealings with her in the way of business, for when he had had occasion to go into Ho Hans's tea-rooms, he was usually after bigger game than the graceful little dancer.

It all came back to him in a flash. He had heard men at the club speaking of the grace of the Little Daffodil and her dancing had enjoyed something of a vogue amongst the young Britishers who were exiled in Shanghai.

The next cutting was also in English and ran:

"A sad fatality occurred this morning, a young Chinese girl, O Ling, the sister of Inspector Ling Chu, of the Native Police, being found in a dying condition in the yard at the back of Ho Hans's tea-rooms. The girl had been employed at the shop as a dancer, much against her brother's wishes, and figured in a very unpleasant affair reported in these columns last week. It is believed that the tragic act was one of those 'save-face' suicides which are all too common amongst native women."

Tarling whistled, a soft, long, understanding whistle.

The Little Daffodil! And the sister of Ling Chu! He knew something of the Chinese, something of their uncanny patience, something of their unforgiving nature. This dead man had put an insult not only upon the little dancing girl, but upon............