Sanderson returns to planet Scadrial (The Hero of Ages, 2008, etc.) where, 500 years later, the scenario is a fantasy Wild West where the largest city, Elendel, despite its unpredictable mists, boasts railroads, electric street lighting and nascent skyscrapers.
Though lesser beings than their godlike ancestors, certain citizens gain magic powers from an ability to metabolize metals. Waxillium Ladrian, a rare Twinborn, can both attract and repel metals using Allomancy and gain or lose bodily mass via Feruchemy. Having spent 20 years in the Roughs—Tombstone in the 1880s, with every day a bad day—expunging evildoers, Wax has learned that House Ladrian, complete with supercilious butler, is all but bankrupt thanks to a profligate uncle. Sadly he returns to Elendel to do his duty and marry a rich heiress. Lord Harms presents his rather too well-organized daughter Steris, who arrives for introductions complete with a 20-page pre-nuptial agreement. Accompanying father and daughter is penniless cousin Marasi, more intelligent and personable and vastly more attractive. Meanwhile, strange crimes are afoot: mysterious thieves, "Vanishers," have stolen consignments from railroad cars, raided parties and taken hostages. It’s eventually deduced that the hostages may be the Vanishers' real targets: all are descended from the same ancient family, and all have specific magic powers. And, at the first social event Wax attends with Lord Harms and the two girls, the Vanishers strike again. Sanderson's fresh ideas on the source and employment of magic are both arresting and original—just don't expect rigorously worked out plot details, memorable characters or narrative depth. Think brisk. Think fun.
Butch Cassidy territory—ignore the tumbleweeds and enjoy.