ABANDONED. YA book about siblings(?) who discover humans are actually from another planet...

[Matt]

This is a book I read sometime around the mid-to-late 1990's. I have no idea when it was originally published, but I would guess 80's or 90's.

I remember almost nothing about it except the big twist at the end: humans are actually beings from another planet that came to earth some thousands and thousands of years ago and "conquered" it. The protagonists, brother and sister if I remember correctly, discover all of this through paintings in a cave. I think also the protags encounter an alien who, we learn, is one of the original earth-beings whose species was sent away.... something like that?

Obviously the details are fuzzy, and I wish I had more to go on, but any help is appreciated!

[Tab]

A stretch, but they are siblings meeting aliens Beckoning Lights ?

Remember anything about the cover?

[Matt]

Tab wrote: "A stretch, but they are siblings meeting aliens Beckoning Lights?

Remember anything about the cover?"

Unfortunately no. I don't think this is it :(

[Lobstergirl, au gratin]

Matt, are you still looking for this book?

[Lobstergirl, au gratin]

Lobstergirl wrote: "Matt, are you still looking for this book?"

No response. Moving to Abandoned.