The Clues Were All There
Within the troglodyte complex of caves, the party encounters the king of the troglodytes. The king is curiously more intelligent than the others and holds a brief conversation with the adventurers, stopped only when the party inevitably gets bored and starts attacking.
After the fight, the adventurers take stock. 'From what the king said, I think it's safe to say we're in the right place.'
'Well, you have been wandering around a pre-generated map for the past two weeks, but sure.'