A world where, instead of aging in years, the people age in knowledge. So, instead of dying once a general age was reached, they die once they achieve a certain amount of knowledge. A man could live forever if he never learned anything, or could die after reading a few choice books. Of course, the knowledge of the land would be regulated, like medical drugs.
A group of adventurers come across a child’s body on their adventures, odd being such a remote location. Their is no detectable sign of violence to the child, nor are their any signs of life. Suddenly the child opens its eyes, looks towards the group and introduces themselves to the adventures.
If this wasn’t odd enough, the child can’t remember where they are from, only their name and age. Stranger yet, the child has a tattoo on their right shoulder of a family crest, to a family that died out over 200 years ago.