Memory fades with time. Ephemeral humans remember few details of their childhood when they are old. When people live many centuries, nothing of their earlier lives remains. When this story takes place, it is two centuries since someone marketed an enhancement to memory that improved capacity and length by a factor of one hundred, allowing those who use it to remember clearly for centuries.
Memory is a powerful thing. One with it can put one without it at a disadvantage. Sudden recall can be staggering in the right time and place. When this story takes place (941ad.). it has been four centuries since a drug was available that allows one to recall the past so vividly they live in it, and suddenly remember all the details they remembered at the time.
In this story we follow the adventures of Taron, who has enhanced memory but suffers flashbacks that bring her into the past as a side effect; and Deneb, who has not enhanced his memory so he can't remember the times they shared. But neither of them remembers the secret they share, a secret that puts them in danger today.
This story happens in Kassidor's 45th century, just before the Instinct reaches the Norbin basin so there is the possibility of violence. The flashbacks take us to the 35th century when violence was almost as common as on Earth today. The 45th century is also before the suntowers so there is less communication with other parts of the planet and many areas were unknown to each other. In many other ways the 45th century was modern. There was amplified and recorded music, grown housing and many other things that made the world, and Norbin in particular, look a lot like it does today.
The memory problems of eternal youth are real, and this story explores a few of them. The main one Deneb and Taron came up against is something many will face when aging is cured, probably just as unknowingly as the characters in this tale. When eternal youth is possible, society will face the same problem Norbin did in the 35th century, and we will go thru the same trouble they went thru. We may already be starting it now because we can all be VERY sure that the cure will be hoarded by the wealthy as it was there.