After you encounter a space with instructions to draw 1 or more Adventure Cards and have drawn the required number of cards, you may investigate. To do so, discard 1 card on your space that is not an Enemy and draw one more card to replace it, which you must encounter.
From what I understand, this is more or less similar to the Prophetess' ability, except the Vampire Hunter can't discard Enemies.
What throws me off in the phrasing is the requirement to draw cards for this ability to work and the "discard one card on your space" clause. Why not say, discard one of the cards you drew., It seems that with the ability as written, it allows you to discard a card you haven't drawn on your current space.
Does that mean the VH can replace any one unwanted non-Enemy card on her space with another one she draws from the Adventure deck?