“It’s a lesson to you that you can’t deceive me, Constable MacPherson,” said Lestrade, with dignity. “No doubt you thought that your breach of duty could never be discovered, and yet a mere glance at that drugget was enough to convince me that someone had been admitted to the room. It’s lucky for you, my man, that nothing is missing, or you would find yourself in Queer Street. I’m sorry to have called you down over such a petty business, Mr. Holmes, but I thought the point of the second stain not corresponding with the first would interest you.”

“Certainly, it was most interesting. Has this woman only been here once, constable?”

“Yes, sir, only once.”

“Who was she?”

“Don’t know the name, sir. Was answering an advertisement about typewriting and came to the wrong number - very pleasant, genteel young woman, sir.”

“Tall? Handsome?”

“Yes, sir, she was a well-grown young woman. I suppose you might say she was handsome. Perhaps some would say she was very handsome. ‘Oh, officer, do let me have a peep!’ says she. She had pretty, coaxing ways, as you might say, and I thought there was no harm in letting her just put her head through the door.”

“How was she dressed?”

“Quiet, sir - a long mantle down to her feet.”

“What time was it?”

“It was just growing dusk at the time. They were lighting the lamps as I came back with the brandy.”

“Very good,” said Holmes. “Come, Watson, I think that we have more important work elsewhere.”

As we left the house Lestrade remained in the front room, while the repentant constable opened the door to let us out. Holmes turned on the step and held up something in his hand. The constable stared intently.

“Good Lord, sir!” he cried, with amazement on his face. Holmes put his finger on his lips, replaced his hand in his breast pocket, and burst out laughing as we turned down the street. “Excellent!” said he. “Come, friend Watson, the curtain rings up for the last act. You will be relieved to hear that there will be no war, that the Right Honourable Trelawney Hope will suffer no setback in his brilliant career, that the indiscreet Sovereign will receive no punishment for his indiscretion, that the Prime Minister will have no European complication to deal with, and that with a little tact and management upon our part nobody will be a penny the worse for what might have been a very ugly incident.”

My mind filled with admiration for this extraordinary man.

“You have solved it!” I cried.

“Hardly that, Watson. There are some points which are as dark as ever. But we have so much that it will be our own fault if we cannot get the rest. We will go straight to Whitehall Terrace and bring the matter to a head.”

When we arrived at the residence of the European Secretary it was for Lady Hilda Trelawney Hope that Sherlock Holmes inquired. We were shown into the morning-room.

“Mr. Holmes!” said the lady, and her face was pink with her indignation. “This is surely most unfair and ungenerous upon your part. I desired, as I have explained, to keep my visit to you a secret, lest my husband should think that I was intruding into his affairs. And yet you compromise me by coming here and so showing that there are business relations between us.”

“Unfortunately, madam, I had no possible alternative. I have been commissioned to recover this immensely important paper. I must therefore ask you, madam, to be kind enough to place it in my hands.”

The lady sprang to her feet, with the colour all dashed in an instant from her beautiful face. Her eyes glazed - she tottered - I thought that she would faint. Then with a grand effort she rallied from the shock, and a supreme astonishment and indignation chased every other expression from her features.