Watson in the conclusion describes the day that Sherlock Holmes was Jack the Ripper. He was standing in a place named Reichenbach Falls. Watson always knew that Jack the Ripper was Holmes but he didn't want to tell anybody because Homes was his friend and he could never do something like that. He remembered Homes talking to him until he fell and died.
Watson life was ending. He sat by the fire in the evening and remembered the day that he saw Holmes as JACK THE RIPPER and when he saw Holmes falling down in Reichenbach falls
In the conclusion watson narrated what has happened. Next he said that ACD wrote about the good dectective Sherlock Holmes and his fabulous cases. Unfortunately, Holmes used cocaine and his life was distorted. Watson also said that he destroyed and hide all the papers that said that Sherlock Holmes was the murderer because he wanted that the world rembered Sherlock by the good dectective he had been.