The heroes are hired by a trade caravan as guards, and travel to the city of Ban Ma Terril. One of the merchants of the city, a weaver named Argol, warns them that something is going on -- people in the city have begun to act strangely: hollow, as if their wills were not their own, as if someone or something had stolen their very souls! The investigation will lead to mystery, intrigue and murder, as the heroes are drawn into the machinations of a secret society that threatens the entire Red Planet! (publisher blurb)