After clearing a mountain pass of a row of Blaster Bugs, the Roughnecks are able to capture Colonel T'Phai, the leader of the Skinnies. After normal interrogation methods fail, High Command orders Carl to use his special abilities. When Carl complies, he discovers "two voices" inside the Skinnie's head. It seems that a small, crab-like Control Bug has been attached to T'Phai, controlling all his actions. It's revealed that the Skinnie population has been enslaved by the Bugs since the Troopers' arrival. The Skinnies' task was to mine a highly unstable material called Xylon that allows for interstellar Bug travel. The Roughnecks then join forces with T'Phai to free the enslaved Skinnie population and prevent a Transport Bug from leaving the planet with the Xylon.