The planet Starlight is controlled by dragons. Because of the depletion in their atmosphere of an essential gas, pheterone, they must search for a way to survive. They know that a network of gas veins exists deep beneath the crust of their planet, but, being dragons, they are not skilled with ways to drill.
One dragon, Magnar, finds humans on another planet he calls Darksphere, captures several of them, and forces them to drill through Starlight's crust in order to release the gas. A man escapes and returns to the planet of humans. He tells everyone about the missing people they call the Lost Ones and how they went through a portal to a dragon planet. Since the portal doesn't always work, he is unable to prove his story, and nearly everyone thinks he is crazy or maybe he murdered the others.
A few believe his story and form a group called the Underground Gateway, which refers to the portal. Unfortunately, the escapee's son is imprisoned and becomes inaccessible, so the Gateway has to try to piece together information as they secretly search for the portal. After many unsuccessful years, they are considered by most to be nothing more than crackpot conspiracy theorists.
One hundred years after the initial enslavement, Adrian Masters, a 24-year-old expert swordsman, sets out on a journey to find the portal to the dragon planet. He is accompanied by Marcelle, a sword maiden of amazing skill whose ideas about how the operation should be carried out conflict with his own. Adrian believes in using stealth and cunning to free the slaves, while Marcelle opts to take a more direct approach. This causes friction between these two warriors, though they respect each other's skills highly.
When Adrian and Marcelle find the slaves, they learn that these longsuffering people have no memory of their origins, making them reluctant to believe the two would-be rescuers, especially since the dragons crush any opposition to their cruel tyranny. Undeterred by the overwhelming obstacles, the two warriors set out to free the slaves and face mortal danger at every turn. As they battle dragons, endure torture, and dispel superstition, they learn that an ultimate sacrifice is the only way they can bring liberty to the oppressed.
