Tarling went back to his lodgings that afternoon, a puzzled and baffled man. Ling Chu, his impassive Chinese servant, had observed those symptoms of perplexity before, but now there was something new in his master's demeanour — a kind of curt irritation, an anxiety which in the Hunter of Men had not been observed before.

The Chinaman went silently about the business of preparing his chief's tea and made no reference to the tragedy or to any of its details. He had set the table by the side of the bed, and was gliding from the room in that cat-like way of his when Tarling stopped him.

"Ling Chu," he said, speaking in the vernacular, "you remember in Shanghai when the 'Cheerful Hearts' committed a crime, how they used to leave behind their hong?"

"Yes, master, I remember it very well," said Ling Chu calmly. "They were certain words on red paper, and afterwards you could buy them from the shops, because people desired to have these signs to show to their friends."

"Many people carried these things," said Tarling slowly, "and the sign of the 'Cheerful Hearts' was found in the pocket of the murdered man."

Ling Chu met the other's eyes with imperturbable calmness.

"Master," he said, "may not the white-faced man who is now dead have brought such a thing from Shanghai? He was a tourist, and tourists buy these foolish souvenirs."

Tarling nodded again.

"That is possible," he said. "I have already thought that such might have been the case. Yet, why should he have this sign of the 'Cheerful Hearts' in his pocket on the night he was murdered?"

"Master," said the Chinaman, "why should he have been murdered?"

Tarling's lips curled in a half smile.

"By which I suppose you mean that one question is as difficult to answer as the other," he said. "All right, Ling Chu, that will do."

His principal anxiety for the moment was not this, or any other clue which had been offered, but the discovery of Odette Rider's present hiding-place. Again and again he turned the problem over in his mind. At every point he was baffled by the wild improbability of the facts that he had discovered. Why should Odette Rider be content to accept a servile position in Lyne's Stores when her mother was living in luxury at Hertford? Who was her father — that mysterious father who appeared and disappeared at Hertford, and what part did he play in the crime? And if she was innocent, why had she disappeared so completely and in circumstances so suspicious? And what did Sam Stay know? The man's hatred of the girl was uncanny. At the mention of her name a veritable fountain of venom had bubbled up, and Tarling had sensed the abysmal depths of this man's hate and something of his boundless love for the dead man.

He turned impatiently on the couch and reached out his hand for his tea, when there came a soft tap at the door and Ling Chu slipped into the room.

"The Bright Man is here," he said, and in these words announced Whiteside, who brought into the room something of his alert, fresh personality which had earned him the pseudonym which Ling Chu had affixed.

"Well, Mr. Tarling," said the Inspector, taking out a little notebook, "I'm afraid I haven't done very much in the way of discovering the movements of Miss Rider, but so far as I can find out by inquiries made at Charing Cross booking office, several young ladies unattended have left for the Continent in the past few days."

"You cannot identify any of these with Miss Rider?" asked Tarling in a tone of disappointment.

The detective shook his head. Despite his apparent unsuccess, he had evidently made some discovery which pleased him, for there was nothing gloomy in his admission of failure.

"You have found out something, though?" suggested Tarling quickly, and Whiteside nodded.

"Yes," he said, "by the greatest of luck I've got hold of a very curious story. I was chatting with some of the ticket collectors and trying to discover a man who might have seen the girl — I have a photograph of her taken in a group of Stores employees, and this I have had enlarged, as it may be very useful."

Tarling nodded.

"Whilst I was talking with the man on the gate," Whiteside proceeded, "a travelling ticket inspector came up and he brought rather an extraordinary story from Ashford. On the night of the murder there was an accident to the Continental Express."

"I remember seeing something about it," said Tarling, "but my mind has been occupied by this other matter. What happened?"

"A luggage truck which was standing on the platform fell between two of the carriages and derailed one of them," explained Whiteside. "The only passenger who was hurt was a Miss Stevens. Apparently it was a case of simple concussion, and when the train was brought to a standstill she was removed to the Cottage Hospital, where she is to-day. Apparently the daughter of the travelling ticket inspector is a nurse at the hospital, and she told her father that this Miss Stevens, before she recovered consciousness, made several references to a 'Mr. Lyne' and a 'Mr. Milburgh'!"

Tarling was sitting erect now, watching the other through narrowed lids.

"Go on," he said quietly.

"I could get very little from the travelling inspector, except that his daughter was under the impression that the lady had a grudge against Mr. Lyne, and that she spoke even more disparagingly of Mr. Milburgh."

Tarling had risen and slipped off his silk dressing-gown before the other could put away his notebook. He struck a gong with his knuckles, and when Ling Chu appeared, gave him an order in Chinese, which Whiteside could not follow.

"You're going to Ashford? I thought you would," said Whiteside. "Would you like me to come along?"

"No, thank you," said the other. "I'll go myself. I have an idea that Miss Stevens may be the missing witness in the case and may throw greater light upon the happenings of the night before last than any other witness we have yet interviewed."

He found he had to wait an hour before he could get a train for Ashford, and he passed that hour impatiently walking up and down the broad platform. Here was a new complication in the case. Who was Miss Stevens, and why should she be journeying to Dover on the night of the murder?

He reached Ashford, and with difficulty found a cab, for it was raining heavily, and he had come provided with neither mackintosh nor umbrella.

The matron of the Cottage Hospital reassured him on one point.

"Oh, yes, Miss Stevens is still in the hospital," she said, and he breathed a sigh of relief. There was just a chance that she might have been discharged, and again the possibility that she would be difficult to trace.

The matron showed him the way through a long corridor, terminating in a big ward. Before reaching the door of the ward there was a smaller door on the right.

"We put her in this private ward, because we thought it might be necessary to operate," said the matron and opened the door.

Tarling walked in. Facing him was the foot of the bed, and in that bed lay a girl whose eyes met his. He stopped dead as though he were shot For "Miss Stevens" was Odette Rider!