When the impetuous Persis Allen marries Union Pacific railroad baron Alex Mackinney, she gets the life of luxury and frontier adventure she hoped for . . . at a price. Caught up at once in the lusty drama of Butte City and Helena, she meets wealthy cattlemen and miners and glimpses the strange poverty of prostitutes and opium smokers. The parites, balls, and flirtations at first seem the ideal backdrop for the handsome and aspiring couple. But a crack appears in this perfect vignette, and no matter how hard a terrified Persis tries to patch the fissure, it widens into a yawning abyss of danger. Alone and stunned into a brutal recognition of the truth, Persis must confront her own choice between life and death.