Holmes and Watson peer through the keyhole of the room and find an unnatural grinning face leering at them. Upon arriving at the family estate, the three find a shaken housekeeper who claims that Bartholomew has not emerged from his locked room all day. Thaddeus concludes by entreating the three to accompany him to the family estate where they will divide up the fortune. On his deathbed, the brothers’ father made them swear they would share the treasure with Mary Morstan, who has some unknown claim in the fortune. Thaddeus proceeds to explain that after searching for years for the treasure, his brother Bartholomew discovered it in a hidden attack in the family house. The following morning, a note was found affixed to the body: it read “Sign of Four”. On his deathbed, the elder Sholto revealed to his sons the existence of the treasure, but just before he could tell them where it was, the face of a bearded man appeared in the window, and the old man suffered a fatal heart attack. Thaddeus goes on to explain that his father always lived in fear of men with wooden legs, and on occasion struck out at perfect strangers who were so handicapped. Sholto reveals that not only has Mary’s father died, but also she is partial heir to a great hidden treasure. Within, they find an eccentric gentleman named Thaddeus Sholto. When the three journey to the Lyceum Theater, Holmes, Watson, and Mary are whisked away in a darkened carriage to a strange house. Holmes and Watson agree to accompany Miss Morstan, and it appears that Watson and Mary are attracted to one another.

The letter itself hints that some injustice has been done to her. Mary goes on to explain that she has received a letter instructing her to go, with the accompaniment of two friends, to Lyceum Theater.

Miss Morstan proceeds to explain that after her father disappeared under mysterious circumstances some ten years ago, she began receiving a large pearl in the mail at annual increments. Mary Morstan, a single young woman who desires Holmes’ advice, soon visits the two. The Sign of the Four begins rather controversially with Holmes engaging in the then-legal pastime of cocaine injections, much to Watson’s disapproval.

Sherlock the sign of four