Earth calls on the Enterprise to intercept two renegade cyborgs, but the human/robot hybrids turn out to be an insidious enemy.
A young man, who has gained the ability to move faster than the eye can see, begins to use his new power to kill his enemies, including the local sheriff, who happens to be his father.
Mulder arrests the murderer of Amber-Lynn LaPierre and discovers a mass gravesite containing the bodies of dozens of missing children.
Walker and the team must beat the clock to save the city of Dallas from a man threatening to release deadly gas into the air.