A Frosty Door

You continue to follow along the path a little on edge from your previous encounter until you come across something unexpected.

You see a door standing in the middle of a clearing in the forest. It shimmers with a faint coat of frost, despite the fairly warm temperature and sunlight.

As you approach, you hear a mechanism and the door opens itself to you revealing a set of stairs, also shimmering with a coat of frost, going up to the next floor.