If you mean the door on the east side of the first area, it must be opened from the north side.
you go to china. find the dragon cave. there will be a door with marks click on it then inspect it than boom the door is open.
You need to do Champions quest to get in ( Dragon Slayer ).
Stocking the shelves.
just click the bush the cave will open !!
First open your map. Then click on Skullhaven. After click on the icon on the left. Go into the mouth of the dragon. Go into into the mid. door.
You say "OPEN DOOR OF EVIL AND BRING ON THE DANCING CHUNKS"
You need to use the Pomegranates (found near the bull's cave) as a sacrifice. Then the door should open.
Stand in front of the door and have a pokemon use the HM move CUT. The door will break and you are able to enter the cave.
its for the quest dragon slayer
by getting a life
All you have to do is go in the cave, get the star out that you get from the museum with all the gods. Then you put the star on the little table in the cave and then the door will open.
Make it by alchemy, or go next to Stornway inn, go down the staircase, and use magic key to unlock purple door. Open the red chest.