Alaskan railroad magnate Curtis Gordon hires engineer Dan Appleton to design a railroad route up the Salmon River to the rich gold country. Gordon turns down the engineer's proposed route in favor of his own, and Appleton quits. Murray O'Neil, a rival builder, hires him and falls in love with his sister Eliza, while Appleton courts Natalie, Gordon's stepdaughter. Following Appleton's plan, O'Neil lays the trail with a bridge crossing the river in face of Gordon's opposition.
Countess Natalya is a glamorous refugee from the Bolshevik revolution. Supporting herself and her ailing sister by dancing in a Shanghai dive, she's is talked into a marriage with a wealthy Chinese gentleman. She has been led to believe that this marriage of convenience is not binding, thus she sees no reason not to marry American diplomat Kenneth Harlan once she's arrived in the States.
Youth meets Ambition and leaves Love, his mother, and his small-town roots for the big city. There, in his search for Experience, he meets Pleasure and hangs out at the Primrose Path with the likes of Temptation and Intoxication. Back home, Youth's mother dies, and Love tries unsuccessfully to reach him. When Youth's money runs out his newfound friends all leave him and he sinks into a life of drug addiction, aided by Habit.
Car racer Burn 'em Up Barnes, son of a wealthy manufacturer, leaves home to make his own way in the world. After being robbed by hoodlums, Barnes joins a group of hobos who take him in and show him the carefree life.
A propagandistic view of the First World War, showing the political greed of the German Kaiser Wilhelm, the resistance of some of his own soldiers, and fanciful prediction of the nature of the war's end.
