There are ruins, scattered about the world, and all are sealed with unbreakable locks.
When all of these locks suddenly open, what emerges?
A cave with weapons sunken into the walls, blades sticking out of the floor and ceiling, and so on. Possibly, any weapon used in it could be torn out of the hand and sink into the stone.
What is a king to do? A prophesy indicates that a certain person is involved with the death of the king, but the prophesy was unclear as to what role - do they cause it or prevent it.