The Stone Mountain Trilogy is composed of Followers of the Light, Children of the Light, and Promise of the Light (Prequel). Followers of the Light is written (although in need of serious editing), Children of the Light is partially written, and Promise of the Light is just an idea with a few passages being taken from FotL and placed there instead.
Followers of the Light - Four teenagers go through a portal leading to another planet, terraformed, with people who've been living there for a few thousand years. They are ruled by an evil tyrant who wants these teenagers killed... because one of them is the true king.
Children of the Light - The king who was good for most of his reign has now gone mad and his children are the only ones who can end his insanity and stop the evil plans of a count manipulating him.
Promise of the Light (prequel) - Three men and a woman travel to the planet for the first time in thousands of years, but one of them betrays the entire planet, killing the royal household and setting himself up as the evil despot. But there is hope... one son has survived. Where is he? On Earth.