California 1849. The snowbound goldfields are limited with countless hopefuls rushing to make their fortune. Among them is poor Irish immigrant Daniel Dillon, his wife Elena and baby daughter, Hope. Lost in a blizzard, exhausted and starving, they stumble upon a lonely hut with a sign above which reads “Thy Kingdom Come”. Fuelled by drink and a lust for gold, Dillon sells his wife and child to the prospector who lives there, in exchange for a gold claim.
Twenty years later Elena and Hope return to the pioneer settlement of Kingdom Come. Although rough and tough, the town is prosperous and Dillon is now a wealthy man of considerable authority, having as his mistress the local madam, Lucia.
Elena and Hope’s arrival coincides with that of a young engineer, Dalghlish, who has come to survey the town for the site new railroad. Symbolising the march to modernity, Dalghlish is the prototype for the New American and a bringer of change. He and Hope fall in love, much to Dillon’s delight, as he envisages a future in which these two will inherit the town. But an unfortunate twist of fate means the railroad must be sited further down the valley, out of Dillon’s control. Feeling angry and betrayed, Dillon runs Dalghlish out of town and the burgeoning romance between Hope and Dalghlish looks increasingly threatened.
Meanwhile, consumed by guilt at his wrong-doing, Dillon has remarried Elena and thrown over his lover, Lucia. Jealousy and rejection take their toll and that one momentary lapse of human weakness of twenty years ago brings a final and terrible retribution.