1, this story begins with Sherlock Holmes' long-winded deduction: Holmes knows that Watson went to the post office and sent a telegram in the morning without knowing it; Judging from the present situation of a watch given to him by Watson, this watch was originally his brother's, and his personality, life track and ending are all clear.

The official story begins with a visit of Miss Mostein. Her strange experiences and strange invitations naturally aroused Holmes' great interest. With their agreement, the story unfolds gradually, one mystery is solved one by one, and new mysteries appear constantly. Here, Holmes' intelligence and wisdom are fully displayed, but there are also setbacks and failures. Finally, the arrested murderer told the background and ins and outs of the case.