It was the spring of 1894, and all of London was shocked by the terrible murder of Mr. Ronald Adair. I wished my late friend, Sherlock Holmes, was still here because this crime had a mystery to it that I knew he would have loved to solve.

Three years had passed since Holmes's death. He had died during a fight with his enemy, Professor James Moriarty, at the Reichenbach Falls in Switzerland. Both of them had fallen into the powerful water below. Now, all I had were my memories of Holmes and the many adventures we had shared together.

My time with Holmes had given me a deep interest in crime, and every day I read the newspapers to look for unsolved robberies and murders. Sometimes, I even tried to use Holmes's methods to solve them, though I wasn’t very successful.

The murder of Ronald Adair was especially interesting to me, and I carefully read all the evidence presented at the inquest. All day, as I visited my patients, I kept thinking about the case. However, I couldn’t figure out how the murder was committed, or who the killer was.

Ronald Adair was the second son of the Earl of Maynooth, who was the governor of an Australian colony. His mother came back to England from Australia in the summer of 1893 for an eye operation. She, Ronald, and his sister Hilda lived at 427 Park Lane in London. Ronald quickly became popular with the upper class of London society. He seemed like a well-liked young man who had no enemies. In the autumn of that year, he got engaged to Miss Edith Woodley, but they ended the engagement by Christmas. There were no bad feelings, and they stayed friends.

People who knew Ronald Adair said he was quiet, modest, and easy to get along with. There was nothing about his life or personality that made it seem like he would meet a violent end. However, he died in a strange and brutal way between 10:00 and 11:20 p.m. on the night of March 30, 1894.

Ronald Adair enjoyed playing card games. He was a member of three card clubs in London and played almost every day, but usually for small amounts of money. On the day he died, he played two rounds of whist at the Bagatelle Club, one in the afternoon and one after dinner. His fellow players—Mr. Henry Murray, Sir John Hardy, and Colonel Sebastian Moran—later said there were no big wins or losses that day. Adair might have lost five pounds, but that was a small amount for someone with his wealth. He was a careful player, though he did win big sometimes. For example, he once won ?420 in a single round with Colonel Moran as his partner.

On the night he died, Ronald Adair came home from his club at exactly ten o'clock. His mother and sister were out visiting someone. The servant said she heard him go into his sitting room on the second floor. She had already lit a fire in the room and opened a window to let out the smoke.

No one heard any noise from that room until Lady Maynooth and Hilda came back home at eleven-twenty.

Lady Maynooth wanted to say good-night to her son, so she tried to go into his room. However, the door was locked from the inside, and he didn’t answer when she knocked and called out. In the end, a servant had to force the door open.

The young man was found dead in a pool of blood near a table. He had been shot in the head with a special bullet designed to cause a lot of damage, and the injury was very severe. There was no weapon found in the room. On the table, there were some notes and coins in small piles, and a scrap of paper with names and numbers, as if Adair had been keeping track of his game wins and losses.

No one could figure out why Adair had locked the door from the inside. It was possible that the killer had locked the door before escaping through the window, but it was a long drop to the ground below.

Under the window, there was a bed of crocuses in full bloom. The flowers and the soil were undisturbed, and there were no marks on the grass between the house and the road.

So, how could the murder have happened? If someone had climbed up to the window, there would have been traces left behind. It was also possible that the shooter fired through the window, but they would have had to be an excellent marksman to cause such a deadly wound with a revolver. Besides, a gunshot would make a lot of noise. Despite a busy cab stand nearby, no one reported hearing anything.

The mystery was made even harder because there seemed to be no motive. The young man had no known enemies, and nothing valuable was stolen. I spent my days thinking about these details, trying to find a new way to understand the case, like Sherlock Holmes would have done. But I made little progress.

One evening in early April, I walked over to Park Lane. A group of people had gathered outside the Adair house and were looking up at his sitting room window. A thin man was sharing his own ideas about what had happened.

I moved closer to hear what the thin man was saying, but his ideas seemed silly, so I stepped back quickly. As I did, I accidentally bumped into an old gentleman and knocked several books out of his hands. The books were old and had nice covers, so I guessed that he must be a collector of rare books. I apologized and helped him pick up the books, but the man just glared at me, turned, and walked away into the crowd.

In the end, my visit to 427 Park Lane didn’t help much with solving the mystery. The house was separated from the street by a low wall and railing that someone could easily climb over. However, the window was too high to reach. There was no drainpipe or anything to help someone climb up, just bare bricks. More confused than before, I walked back to my place in Kensington.

I had just been in my study for five minutes when the maid told me I had a visitor. To my surprise, it was the old book collector I had bumped into on Park Lane. His wrinkled face was partially hidden by his white hair. He was holding at least a dozen of his precious books under his arm.

"You're surprised to see me, sir," he said in a croaky voice.

"I am indeed," I replied.

"Well, to be honest, I felt guilty after our last meeting. I wanted to tell you that if I seemed rude, it wasn't intentional, and I'm very grateful that you helped me with my books."

"It was nothing," I said. "How did you know who I was?"

"Actually, I live very close to you. My little bookshop is at the corner of Church Street. Maybe you collect books yourself? I have volumes on Swiss birds, unsolved crimes, and travels in the Himalayas—each one a bargain. Just five of these books would fit nicely on your second shelf, don't you think?"

I glanced at the bookshelf. When I looked back, the old man had changed into Sherlock Holmes.

I stared in shock for several seconds. Then, a faint mist appeared before my eyes, and for the first and only time in my life, I fainted.

I woke to find myself seated in an armchair, my collar open at the neck. Holmes was standing over me, a look of tender concern on his face. "My dear Watson," he said in that familiar voice, "I owe you a thousand apologies. I had no idea you'd be so affected."

I gripped his arm. "Holmes, is it really you? Are you alive? How did you climb out of that waterfall?"

"I'll happily tell you the whole story," smiled Holmes, "but are you sure you're in a fit state to hear it?"

"I'm fine," I promised him. "Holmes, I can hardly believe my eyes. It's so incredible seeing you standing here in my study." Again, I grabbed his sleeve and felt the thin, muscular arm beneath it. "You're not a spirit, that's for sure ... My dear chap, I'm so happy to see you. Sit down and tell me everything."

Holmes sat down in the armchair across from me. He was still wearing the worn coat of the bookseller, but the rest of his disguise and the books were in a messy pile at his feet. Despite looking a bit weak and pale, he still had that familiar sparkle in his eyes.

"I didn't have any trouble getting out of the waterfall, Watson," he said, "because I never actually fell into it, even though Professor Moriarty tried his best to make me fall. He knew he was done for and just wanted to take revenge on me. He charged at me, and we fought on the edge of the waterfall. It was a close call for a moment.

"Luckily, I know some baritsu, an old Japanese style of wrestling, and I managed to get free from his hold. Then Moriarty lost his balance. He flailed his arms but couldn't catch himself. He screamed loudly as he fell, hitting a rock before disappearing into the roaring water."

I listened in amazement to his explanation. "But what about the footprints?" I asked. "I saw two sets going up the path and none coming back."

"I’ll explain," said Holmes. "When I saw Moriarty fall, I realized I had a unique chance. Moriarty wasn't the only one who wanted to kill me. At least three of his followers also wanted me dead. They were dangerous, and I would always be looking over my shoulder if they were still after me. But if everyone thought I was dead, these men would stop searching for me. This way, I could work quietly to bring them to justice. All of this thought crossed my mind before Moriarty’s body even reached the bottom of the waterfall."

"But if I was going to fool everyone, I couldn't leave another set of footprints on the path. My only chance was to climb the cliff next to the path. In your account of these events in The Final Problem, which I enjoyed very much, you said the cliff was smooth and vertical. That wasn't completely true.

"In reality, I found a few small footholds and a narrow ledge about halfway up. Climbing that cliff was very difficult. The waterfall roared below me, and it felt like Moriarty’s screams were coming from the water. One small mistake could have been deadly. Several times, I almost fell because the grass came out in my hand or my foot slipped on the wet rock. But I kept going and finally reached the narrow ledge covered with soft green moss. I stayed there hidden while you and the others searched for me."

"Eventually, when you all thought I was dead, you left and I was alone.