Percy Phelps was one of my best friends at school. He was an excellent student and won every prize the school had. Many of the other boys were jealous of him. They called him "Tadpole" Phelps because he was small, and he was often bullied. This did not stop him, though. He went on to get a place at Cambridge University, where he earned a first-class degree. With help from his uncle, the famous politician Lord Holdhurst, he got a good job at the Foreign Office.

I lost contact with my friend at this point, so I was surprised to get a letter from him one day in July 1889. He wrote:

My dear Watson,

No doubt you remember your old friend "Tadpole" Phelps. You will recall how I had an important job at the Foreign Office. All was going well until about nine weeks ago, when something terrible happened that destroyed my career. It caused me a mental breakdown, and I am only just starting to recover. I am still very weak and cannot travel. Do you think you could bring your friend, the detective Sherlock Holmes, to see me? He may be the only person who can help.

Your old schoolmate,

Percy Phelps.

I was very moved by the letter and immediately went to visit Holmes to see if he was interested in the case. I found him at his Baker Street home, looking out of his window, looking bored. "Do you have a case for me, Watson?" he asked. "I really need a case."

"Maybe I do," I said, and showed him the letter. When he had read it, I saw a gleam in his eye and knew his curiosity was piqued. He immediately began putting on his coat.

"Where are you going?" I asked.

"To see Mr. Phelps. There’s no time like the present. Coming, Watson?"

We were lucky to catch an early train at Waterloo, and in just over an hour, we arrived at Briar House, Phelps’s home near the town of Woking in Surrey. It was a large house with a beautiful garden. The butler showed us into an elegant drawing room. A few moments later, a plump young man entered and greeted us warmly.

"I’m so glad you’ve come," he said. "Percy was hoping you would."

"You’re not a member of the family," said Holmes.

The man looked surprised. "How did you know?"

Holmes pointed to the initials on the locket hanging from his neck: J. H.

"Oh, well spotted!" he said. "My name is Joseph Harrison. I may not be a Phelps, but Percy is engaged to my sister Annie, so I will be related to him by marriage. I’ll show you in now if you like—he’s eager to see you."

The ground-floor room was large and airy, with pleasant views of the garden. My old friend was lying on a sofa near the open window, looking very pale and tired. A woman was with him, who introduced herself as Annie Harrison.

Phelps smiled weakly when he saw me. “I barely recognize you with that moustache, Watson, but I suppose I must have changed, too. And I presume this is your famous friend, Mr. Holmes?”

I introduced them, and we sat down.

“I don’t want to waste your time, Mr. Holmes,” said Percy, “so I’ll get straight to the point. I was a happy and successful man with a good job in the Foreign Office, and I was about to marry a wonderful woman, when something terrible happened that ruined my life.

“Around nine weeks ago, my uncle Lord Holdhurst, the Foreign Minister, called me into his private office. He took a roll of pale blue paper out of his desk drawer. ‘This,’ he said, ‘is a secret treaty between England and Italy. It’s very important that no one finds out about it. The French government would pay a lot of money to learn what’s in this treaty. I wouldn’t let it out of my sight, but I need it copied. I want you to take it now and lock it in your desk. When everyone’s left for the day and you’re alone, you must copy it. When you’ve finished, lock the original and your copy in your desk and give them to me tomorrow morning.’ So I took the paper and—”

“Excuse me,” interrupted Holmes. “Were you alone during this conversation?”

“Yes, quite alone.”

“And does your uncle have a loud voice?”

“No. In fact, it’s very quiet.”

“Thank you,” said Holmes, closing his eyes. “Please continue.”

“I did what I was told and waited for the other clerks to leave for home. One of them, Charles Gorot, had some work to finish, so I went out to get something to eat. When I returned, he was gone.

“I was eager to start copying because I knew that Joseph Harrison—the man you met just now—was going to be on the eleven o’clock train to Woking, and I wanted to ride down with him.

“When I looked at the treaty, I understood why my uncle was so anxious to keep it secret. Without going into details, it explained what the British and Italian navies planned to do if France attacked Italy in the Mediterranean.

“I started copying it, but it was slow work. By nine o’clock, I had only copied nine of the twenty-six sections. I realized I probably wouldn’t catch that train. Feeling drowsy, I decided I needed a cup of coffee to wake myself up.”

“I rang the bell to call the caretaker, Mr. Tanner, who has an office on the ground floor. To my surprise, a woman answered the bell. She was a large, red-faced, elderly lady, who introduced herself as Mr. Tanner’s wife. I asked her for coffee, then went back to my work. After about twenty minutes, I wondered why the coffee hadn’t arrived and decided to check.

“My room was on the top floor of the building, leading to a corridor that ended in a curving staircase. There were no other rooms along that corridor. Halfway down the staircase, there is a landing with another corridor that leads to a side door used by servants and clerks. At the bottom of the staircase is the caretaker’s office.

“I went down there and found Tanner fast asleep with the kettle boiling furiously on the stove. I removed the kettle, which was already boiling over, and turned off the stove. I was about to wake him up when a bell above his head rang loudly and he woke up with a start. ‘Mr. Phelps, sir!’ he cried.

“‘I came down to see if my coffee was ready,’ I explained.

“He looked at me and then up at the still ringing bell, his face showing more and more surprise. ‘That’s the bell in your room, sir. If you’re here, then who’s ringing it?’

“A cold hand seemed to close around my heart at that moment. Someone was up there in the room with the precious treaty.”

Percy Phelps shifted uncomfortably on his sofa as he remembered how scared he felt at that moment. “In a panic, I ran back up the stairs. I didn’t pass anyone on the way, and there was no one in the room. Everything was just as I had left it, except the treaty was gone from my desk. The copy was still there, but the original was missing.

“I knew right away that the thief must have come in through the side door on the floor below. If he had come from the ground floor, I would have met him coming the other way.”

“Are you sure he wasn’t hiding in the room or in the corridor outside?” asked Holmes.

“Impossible,” said Phelps. “There’s nowhere to hide in either place.”

“Thank you. Please continue.”

“Tanner saw from my face that something was wrong and followed me as I rushed down to the side door. It was closed but unlocked. I remember, as we opened it and ran outside, hearing three chimes from a nearby clock. It was quarter to ten.”

“That’s very helpful,” said Holmes, making a note on his shirt cuff.

“The night was dark,” continued Phelps, “and a thin rain was falling. There was no one in Charles Street. At the junction with Whitehall, we found a policeman. ‘A robbery has been committed,’ I gasped. ‘A very important document has been stolen from the Foreign Office. Has anyone passed this way?’

“‘The only person who’s come by in the fifteen minutes I’ve been here was a large, elderly lady,’ said the policeman.

“‘That was my wife,’ said Tanner. ‘The thief must have gone the other way. Come on, sir.’ The caretaker pulled at my sleeve, but I wasn’t satisfied. I started to suspect the Tanners. I asked the policeman more about the woman. He couldn’t say where she had gone, but said she had passed by in the last five minutes.

“‘You’re wasting time, sir,’ said Tanner. ‘The thief is getting away.’

“‘Where do you live, Mr. Tanner?’ I asked him.

“‘16 Ivy Lane, Brixton,’ he answered, ‘but that’s not important. Let’s go and search at the other end of the street.’

“We did so and found it full of rushing traffic and people eager to get home on such a wet night. There were no loiterers to tell us who had passed.

“We returned to the office and searched the stairs and corridors but found no footprints or any other trace of the thief. We examined the room—the walls, ceiling, and floor—and saw no sign of a secret entrance. The windows were some thirty feet from the ground and both were fastened on the inside. I would swear on my life that whoever stole the treaty could only have come through the door.”

“What about the fireplace?” asked Holmes.

“There is none—the room is heated by a stove.”

Holmes’s sharp eyes were moving about almost as if he were in the room himself, examining it for clues. “You say the thief left no trace. What about smell?”

“We never thought of that—but I don’t remember any.”

“How was the bell rung?”

“The bell rope hangs from a wire just to the right of my desk. Whoever rang it must have come right up to the desk to do it. But why would a thief wish to ring the bell? It doesn’t make any sense.”

“I agree; it’s very strange,” said Holmes.