#sherlock really likes getting himself yanked around lol
Sherlock and John finds Bartholomew’s corpse with a slip of paper that had 4 crosses drawn on it.
Mary and Bartholomew’s twin brother Thaddeus catch up to them, and the latter notices that the Treasures of Agra is gone.
The last person to meet Bartholomew is Thaddeus and he panics, knowing that the people will mostly suspect him of being the killer even though he didn’t do it.
Sherlock calms him down and gets him to contact the police and explain the situation.
Once Thaddeus leaves, Sherlock tells Mary that this is their last chance to turn back before they get any deeper into the case.
Judging from the way Bartholomew died, it was clearly done by a professional. He proves this getting John to look behind the corpse’s left ear, which was pricked by a poisoned needle. If they continue, they would definitely be targeted too.
Both Sherlock and John try to persuade Mary not to pursue the matter any further, as they can’t guarantee Mary’s safety. However, Mary insists on finding the perpetrator, otherwise Thaddeus might really end up being blamed as the murderer.
Sherlock is impressed at how good Mary was at coming up with counterarguments. She claims that her aim is to help someone, but Sherlock knows that she simply wants to find the perpetrator to find the treasure. However, he still can’t figure out why she needs that treasure so much.
To find out, Sherlock gives Mary a condition. They didn’t need to find the treasure to prove Thaddeus innocence in the matter. To see if Mary truly wanted to help Thaddeus, he asks her to figure out how it prove it herself.
Mary looks around the room before telling Sherlock her deductions. She surmises that there must have been 2 people responsible for these murder. One of the murderers came in through the secret attic. It was from there that they shot the poisoned needle at Bartholomew.
The other is the man with the artificial leg who Sholto feared, judging from the tracks on the window and floor. Also, she believes that one of them must have been Jonathan Small, the sole British name in the map his father had.
She then goes on to say that the Treasures of Agra must have been the possession of those 4 people signed on the map. They were in prison while Sholto and her father had been prison guards there. They must have negotiated with the two into helping them escape in exchange for a share in the treasure, but Sholto must have taken the treasure for himself.
Lastly, she claimed that the symbols on the paper left next Bartholomew’s corpse must have been to signify that the four of them have a right to that treasure.
Everything Mary deduces was in line with Sherlock’s deduction.
It is at this time that Assistant Inspector Greyson turns up. (Sherlock emphasizes the word “assistant” when greeting him, much to the latter’s annoyance.) When Mary tries to explain the Small was the real perpetrator, but Greyson was adamant that it was Thaddeus.
As the police tries to take Thaddeus to the station, Mary rushes forward and tells him that they will prove his innocence. Then, in a low voice, she asks if he told them about the treasure and he whispers negatively.
Now they have no choice but to catch the real killer to prove Thaddeus’ innocence. However, Mary can’t figure out where Small went.
Sherlock urges her to look at the killer’s footsteps again. It seems that the killers must have knocked over one of the chemicals that Bartholomew was using as an experiment, and stepped on it. This chemical has a strong smell and cannot be washed off.
So Sherlock gets Wiggins to bring over a hunting dog. They use this dog named Toby to follow the smell stuck on the shoe of the killer.
Mary is wearing heels, so John convinces him to go back to Baker Street while they hurry to find the killer.
Upon hearing the circumstances, Hudson imagines all she could do if she had that amount of money, like buying clothes and going on overseas trips. However Mary said she did not need that amount of money. All she wants is to live peacefully with John.
Ms. Hudson remembers Sherlock telling her that Mary was hiding something, but Ms. Hudson doesn’t believe Mary was lying just now.
After retiring to the room Ms. Hudson offered her in Baker Street, Mary thinks about how she doesn’t need the treasure, but she must get her hands on it, otherwise she’s going to lose John.
