He died in Venezuela. He did not marry, so no one knew he had a son.'
And this son called himself Stapleton?
Yes, and the son was both bad and clever. He wanted the Baskerville money. There were only two Baskervilles left alive - Sir Charles and Sir Henry. If they died, Baskerville Hall would belong to Stapleton.
What about his wife? Why did Stapleton say she was his sister?