The Dino-Riders are perplexed by a recent onslaught of peculiar earthquakes. When Tagg goes to help some thirsty dinosaurs reclaim their watering hole, he stumbles upon a Rulon tunneling operation that is responsible for the tremors. Although Tagg is captured by the Rulons, Llahd gets away and alerts Questar to the trouble. Our heroes must find Tagg and stop their enemies before the tunnel breaks through the bottom of the ship.