The Giant Drill was a mining drill machine for drilling out iron ore, so King Andrias could make more Frobots and other weapons of war. It was getting dangerously close to the underground city, Proteus.
Background[]
The Wartwood Resistance (Anne, Sasha, and the Plantars) enter Proteus and are taken to meet Parisia, an elderly olm who refuses to take them to see the Mother of Olms. She has the entire city in denial over the tremors caused by the drills and has everyone convinced that they are simply earthquakes that will pass soon. She banishes the group again, but when the tremors get worse, they rush to the surface. Anne, Sasha, and the Plantars try to stop the drill and tell Lysil and Angwin to wait inside the cave as sunlight hurts the olms. They fail to turn off the machine, forcing Lysil and Angwin to both agree to rush to the surface and destroy the drill themselves; falling through the ground and back into the city.
Despite the obvious proof, Parisia is still in denial and accuses the heroes of making it all up. Sasha, having had enough of her claims, yells at her. She empathizes with Lysil and Angwin's plight, as she knows what it is like to not be given another chance, and calls her a "snooty despot" for not acknowledging the twins' heroism. As they prepare to leave, Parisia stops them and admits that she is impressed with how Sasha talked back to her, as no one had done that in years. She finally decides to allow them to see the Mother of Olms and, reluctantly, bring Lysil and Angwin back in, under the condition that they be supervised.