Ever since the war that nearly destroyed the Archayan Republic, Harius has struggled to find peace. His primitive race of winged humans spent years fortifying their nation against another invasion from the flightless yet technologically superior Nayzite Sovereign out to conquer the world. But when it's discovered that the Sovereign is developing war machines capable of overrunning the Republic's mountain stronghold, Harius begins to fear that the divine beings his people worship have forsaken them.

Then, one day, the leader of his spiritual order calls on Harius to guard a sacred key capable of unlocking a portal that leads back to the realm of the Divine. Believing this calling will help him find peace, Harius recommits to his training as a Zenark warrior, so he can wield the infinite power of the celestial flame in the key's defense. As he trains, he will fight several battles to help secure an alliance between the Republic and a powerful Nayzite kingdom to defend against Sovereign aggression. Through it all, Harius will need to learn what the key can unlock within himself before he is tracked down by an adversary who will stop at nothing to destroy him.