The plot begins when Mary Morstan presents the mystery of her missing father. Holmes pursues the case, encountering further secrets and strange events in the process, ultimately solving the mystery.
Explanation
He is attracted to her, but is certain that their unequal social, and particularly financial, statuses will stand in the way of a future for them together
It sounds like you are understanding what is being spoken about and you are showing that you are caring about what the person is saying while giving them your undivided attention.
