I've gotten the flame power (the little fire icon is in the upper righthand corner) and I follow the green arrows all the way up into a room in the north eastern corner...you enter the room, there is a fire altar in front of you, a long narrow passageway to the right, and at the end of the room is a chest with four green gems around it.
I've opened the chest - and I put Dee in my party so that I could pick up th egems. I can figure out nothing else to do in this room! What do I do next?!?