After the death of Sherlock Holmes, Dr.John Watson examined the case of Ronald Adair who was murdered in the accessible room. The door was locked on the inside, and the window which was opened was high at least twenty feet from the ground. Mr.Adair was a member of several card clubs. Before he was dead, he had a play at the latter club with Mr.Murray, Sir John Hardy, and Colonel Moran.
While Watson strolled on Oxford Street after he made just a little progress of the investigation, he struck against an old man. Watson wanted to apologize to him, but he disappeared in the crowd. At Kensington, the old man walked in front of Watson’s study table. He tricked Watson to look at the shelf, then when Watson turned his head back Sherlock Holmes appeared and smiled at Watson. Watson had fainted away. Holmes does apologise to him and answer a thousand questions of Watson after he woke up.
Holmes narrated the story of his two years of death and then invited Watson to go to Camden House, which opposite to Holmes & Watson's old quarters. Holmes planned to meet someone there. A man carried a gun in his hand got in the house and looked through the window to observe the quarters. He shot the shadow of someone standing at the window. Suddenly, Holmes tackled him, and Watson struck him with his revolver. Lestrade rushed into the room and caught him. It was Colonel Moran. Lestrade and Holmes greeted each other.
Colonel Sebastian Moran was accused of murder Ronald Adair. The killing motive was that Moran was cheating in the club and Adair probably known about it. Holmes & Watson returned to the quarters to meet Mrs.Hudson. The strange dummy or a wax model that Sherlock asked Mrs.Hudson to bring it to the window. Holmes lit a cigar and continue to write his collection of M’s, which contained Moriarty, Morgan, Merridew, Mathews, and the last one is Moran.