When costume-maker Ellie Moore suddenly finds herself out of a job in the middle of a bleak Chicago winter, she uses her knowledge of theatrical disguise to secure a position as an undercover operative with the Pinkerton Detective Agency. Her assignment: find the culprit behind the theft of silver shipped from the mines near Pickford, Arizona.
Disguised as Lavinia Stewart, a middle-aged widow, Ellie begins her investigation. Soon she finds she must also pose as the dazzling young Jessie Monroe, whose vivacious personality encourages people to talk.