“My dear old Dick, you have been making a fuss about it.  You will probably find the door open when you go up.”

“And I’ll know who has been playing this stupid trick,” Morriston said wrathfully.

“A footman making love to a housemaid turned the key in a panic at being trapped,” Kelson said to his host.

“I dare say,” Morriston replied with a laugh of ill-humour.  “And he’ll have to pay for his impudence.”

That explanation by its feasibility was generally accepted as the simple solution of the mystery.

“Come along!” Morriston called.  “We’ll all go up, and see whether the door is open or not.  We shall just be in time to catch the sunset.”

He led the way through the hall and the corridor beyond and so up the winding stairs.

“What, not open yet?” he exclaimed as the last turn showed the workman busy at the lock.  “Well, this is extraordinary.”

The locksmith was kneeling and working at the door, while the footman stood over him holding a candle.

“The key is in the lock, inside, isn’t it?” Morriston asked.

“Yes, sir,” the man answered.  “There is no doubt about that.”

“How do you account for it?”

The man looked up from his task and shook his head.

“Can’t account for it, sir.  Unless so be as there is someone inside.”

“Can you open it?”

“Yes, sir.  I’ll have it turned in a minute.”

He took from his bag a long pair of hollow pliers which he inserted in the lock and then screwed tightly, clutching the end of the key.  Then fitting a transverse rod to the pliers and using it as a lever he carefully forced the key round, and so shot back the lock.

There was a short pause while the man unscrewed his instrument; then he stepped back and pushed open the door.

Morriston went in quickly.  “There is the key, sure enough,” he said, looking round at the inside of the door.  He took a couple of steps farther into the room, only to utter an exclamation of intense surprise and horror; then turned quickly with an almost scared face.

“Go back!” he cried hoarsely, holding up his hands with an arresting gesture.  “Kelson, Mr. Gifford, come here a moment and shut the door.  Look!” he said in a breathless whisper, pointing to the floor beneath the window through which the deep orange light of the declining sun was streaming.

An exclamation came from Kelson as he saw the object which Morriston indicated, and he turned with a stupefied look to Gifford.  “My—!”

Gifford’s teeth were set and he fell a step backward as though in repulsion.  On the floor between the window and an old oak table which had practically hidden it from the doorway, lay the body of a man in evening clothes, one side of his shirt-front stained a dark colour.  Although the face lay in the shadow of the high window-sill, there was no mistaking the man’s identity.