Mary's death caused irreparable pain to the two of them, and their relationship became complicated and delicate.

Watson's hallucinations become a part of his daily life, as if Mary is still with him.This hallucination not only deepened his longing for Mary, but also intensified his misunderstanding and resentment towards Shylock.Believing that Shylock was the cause of Mary's death, he chose to cut off contact with him and seek help from a psychiatrist.

Sherlock, on the other hand, fell into substance abuse and his mental state deteriorated.When Smith's daughter, Faith, found him, he tried to avoid her pleas for help, using the excuse of being busy.However, before Faith leaves, Sherlock suddenly realizes her plight and spends the night with her.This brief relationship made Sherlock realize that Faith was also influenced by Smith and became his victim.

As the story develops, we discover that Smith's goals are much more than that.Sherlock is horrified that he plans to kill anyone.In order to expose Smith's crime, Sherlock did not hesitate to reveal his identity on his blog, and even filled his room with photos of him, beating him with guns to vent his anger.

With Watson's help, Sherlock gradually got rid of his psychological dilemma, and the relationship between the two was repaired.However, with the appearance of Smith, their lives were once again in danger.Not only did Smith attempt to kill Sherlock, he confessed to his crime and expressed his obsession with killing.

At this critical moment, Watson arrived in time and rescued Sherlock who was choked by Smith.Sherlock's wit allowed him to install a recording pen in the crutch sent by Watson in advance, and successfully recorded Smith's confession.After the matter was resolved, Sherlock realized that Faith who came to him before was just an illusion, and the real Faith was a strange woman.

The climax of the story reveals that Smith's fake daughter was actually a psychiatrist in disguise, and her true identity turned out to be Sherlock's sister Euros.The appearance of Eurolos made everything confusing. She raised her pistol and shot at Watson, making the whole story fall into a greater mystery.