Minnesota's winter is freezing cold, but its market for guns has never been hotter.

February 1922 - Prohibition has reached a fever pitch, transforming lowly bootleggers and gangsters into wealthy businessmen beyond sanction. The city of St. Paul, Minnesota, known to the criminal underworld as Crooks' Haven, has a rule for out-of-town mobsters: Come visit anytime; just pay your bribes and keep your criminal activity outside the city limits.

Niklas and Kessler Kristofferson, Danish brothers recently returned from the Great War, recognize this as an opportunity. As military gunsmiths, they had access to the most fearsome weaponry the planet had ever seen, much of it in pieces and parts the U.S. government had forgotten on the battlefields of France. After quietly smuggling the machine guns home, they now have an arsenal to sell. And their first client, a Sicilian mobster from the mean streets of Chicago, seems eager to buy.

But dealing with criminals is never straightforward, especially when the goods they are selling can be turned against them the minute they trade hands. Facing unscrupulous gangsters, corrupt police, and the one principled detective left in the city, the brothers must rely on their guile and the few friends they have to survive. A single misstep may rob them of their fortunes-or deliver their corpses to the bottom of the frigid Mississippi River.