In 1920s Chicago, postal employee Saul Imbierowicz is unwittingly swept up in a city-wide conflict between rival gangs, federal agents, and supernatural forces beyond his control.
After striking out on his own from his overbearing Jewish family, Saul quickly becomes involved with the seductive and mysterious Moira. He soon becomes mixed up in the events of the St. Valentine's Day Massacre, witnessing the shooting and fleeing from the scene after Moira takes a bullet and is presumed dead.
However, Moira is far from dead, and due to her influence Saul finds himself increasingly entangled in the rival factions seeking control over the city, coming face to face with Bugs Moran, Al Capone, and the federal agents pursuing both.
Everybody wants something from Saul, but will he be able to save himself and his family, and uncover the supernatural secrets of the city, before it's too late?