The futuristic realm of Terrana, now lies in ruins. Its great past lost in a present of perpetual war. When Jack, a precocious young orphan, reactivates the last of the thinking machines, Xyber 9, he becomes the Chosen One and takes on the task of destroying Machestro, the evil ruler of the underworld. With Xyber 9's power, Jack is able to journey through Machestro's underworld and to other futuristic lands, fighting intergalactic evil.