“I give you five minutes, Mr. Holmes.”

“One is enough, Lady Hilda.  I know of your visit to Eduardo Lucas, of your giving him this document, of your ingenious return to the room last night, and of the manner in which you took the letter from the hiding-place under the carpet.”

She stared at him with an ashen face and gulped twice before she could speak.

“You are mad, Mr. Holmes—­you are mad!” she cried, at last.

He drew a small piece of cardboard from his pocket.  It was the face of a woman cut out of a portrait.

“I have carried this because I thought it might be useful,” said he.  “The policeman has recognized it.”

She gave a gasp, and her head dropped back in the chair.

“Come, Lady Hilda.  You have the letter.  The matter may still be adjusted.  I have no desire to bring trouble to you.  My duty ends when I have returned the lost letter to your husband.  Take my advice and be frank with me.  It is your only chance.”

Her courage was admirable.  Even now she would not own defeat.

“I tell you again, Mr. Holmes, that you are under some absurd illusion.”

Holmes rose from his chair.

“I am sorry for you, Lady Hilda.  I have done my best for you.  I can see that it is all in vain.”

He rang the bell.  The butler entered.

“Is Mr. Trelawney Hope at home?”

“He will be home, sir, at a quarter to one.”

Holmes glanced at his watch.

“Still a quarter of an hour,” said he.  “Very good, I shall wait.”

The butler had hardly closed the door behind him when Lady Hilda was down on her knees at Holmes’s feet, her hands outstretched, her beautiful face upturned and wet with her tears.

“Oh, spare me, Mr. Holmes!  Spare me!” she pleaded, in a frenzy of supplication.  “For heaven’s sake, don’t tell him!  I love him so!  I would not bring one shadow on his life, and this I know would break his noble heart.”

Holmes raised the lady.  “I am thankful, madam, that you have come to your senses even at this last moment!  There is not an instant to lose.  Where is the letter?”

She darted across to a writing-desk, unlocked it, and drew out a long blue envelope.

“Here it is, Mr. Holmes.  Would to heaven I had never seen it!”

“How can we return it?” Holmes muttered.  “Quick, quick, we must think of some way!  Where is the despatch-box?”

“Still in his bedroom.”

“What a stroke of luck!  Quick, madam, bring it here!” A moment later she had appeared with a red flat box in her hand.

“How did you open it before?  You have a duplicate key?  Yes, of course you have.  Open it!”

From out of her bosom Lady Hilda had drawn a small key.  The box flew open.  It was stuffed with papers.  Holmes thrust the blue envelope deep down into the heart of them, between the leaves of some other document.  The box was shut, locked, and returned to the bedroom.