A nocturnal assault by Tendril demolishes the Earth Corps base, prompting a chase into the depths of the Earth, but even with the help of another Mutore species, the rock-bodied "Granites," they are forced to retreat back to the surface. When their budget is summarily cut by Senator Masterson, a crooked politician in Blackthorne Shore's shady pocket, they are approached by Sandra Shore, Blackthorne's sister, who has learned of her brother's sinister plot to liberate Metlar. Funded by Sandra, the team constructs new vehicles and embarks back below the Earth's surface, tracking D'Compose and Tendril to the city of the Granites, where an ensuing battle frees Metlar from Magnokor's hold. Having pilfered the Earth Corps's engineering schematics via his ties to Masterson, Blackthorne joins the fray, now equipped with his own battle-suit whose magnetic powers he wields against Metlar, only to be derailed by Tendril's interference while Sandra falls victim to the mutative touch of D'Compose.