For years, frontier lawman turned big-city senator Waxillium Ladrian has hunted the shadowy organisation the Set - with his late uncle and his sister among their leaders - since they started kidnapping people with the power of Allomancy in their bloodlines. When Detective Marasi Colms and her partner Wayne discover stockpiled weapons bound for the Outer City of Bilming, it opens up a new avenue of investigation. Conflict between Elendel and the Outer Cities only benefits the Set, and their tendrils have now reached the Elendel Senate, whose corruption Wax and Steris have sought to expose, and Bilming is further entangled.