It was nearly eleven o'clock at night, and Colwyn, getting up from a table where he had been busily writing, walked to the window and looked down on the deserted street beneath. It was a nightly custom of his. He lived, as he worked, alone, attended only by a taciturn manservant who had been with him for many years. He accepted with characteristic philosophy the view that a man who spent his time unveiling shameful human secrets had no right to share his life with anybody. Even the articles of furniture of his lonely rooms, if endowed with any sort of entity, might have worn a furtive air in their consciousness of the secrets they had heard whispered in their owner's ears by those who had sought his counsel and assistance in their trouble and despair. There had been many such secrets poured forth in those lonely rooms, perched up high above the roar of the London traffic. It was the Confessional of the incredible.

As Colwyn stood at the window, the electric bell of the front door rang sharply through the empty building. Looking down into the street, he saw the figure of a man in the doorway beneath. He glanced at his watch. It was late for a visitor. He walked to the lift at the end of the passage and descended. As he did so, the bell in his rooms once more pealed forth beneath the pressure of an impatient hand.

The visitor, revealed by the light in the hall, was a young man muffled in a thick overcoat for protection against the sharp autumn wind which was blowing along the rain-splashed street. He stepped inside the door as Colwyn opened it, and, glancing at the detective from a pair of dark eyes just visible beneath the flap of his soft felt hat, said:

"Are you Mr. Colwyn?"

"Yes. What can I do for you?"

"I am afraid it is a very late hour for a visit," said the other, brushing the rain drops off his coat as he spoke, "but I should be very glad if you could spare me a little time, late as it is. I have come from the country to see you."

Colwyn nodded without speaking. Strange adventures had come to him at stranger hours. He showed the way to the lift, switched off the electric light he had turned on in the passage, and ascended with his visitor to his rooms. There his companion, with an impulsiveness which contrasted with the detective's quiet composure, again spoke:

"I want your assistance, Mr. Colwyn."

"Will you not be seated?" said the detective, as with a swift glance he took in the external attributes of his young and well-dressed visitor.

"Thank you. I regret to disturb you at such a late hour, but the train I travelled by was greatly delayed by an accident. I thought at first of postponing my visit till the morning, but it is so urgent—to me, at all events—that I determined to try and see you to-night."