LONG AGO, in a "land belonging to no one," a lonely, fifteen-year-old child named Gregor is exploring the treacherous rock formations at the base of the fabled Two-Pronged Mountain. He reaches into a crevice and withdraws something the likes of which he has never seen: a heavy fragment of perfectly smooth black glass. He hurries the discovery away, hoping to contribute it to his small cache of obscure treasures, which includes broken pieces of once-extravagant china and a long, razor-sharp tooth from the jaw of an unknown beast. But when Gregor arrives at his homestead and displays the fragment at the family hearth, his father utters a stunned reaction in a single word: "Obsidian…." For it seems that with one spontaneous action, Gregor has unknowingly summoned a horrible force that could set blood against blood and cast everyone he has ever known into mortal danger. As father and son race back towards the mountain to try to prevent what has already begun, a massive black cloud on the far horizon slowly begins to advance.