A circus rider makes a hit in the automotive industry but can't find happiness.
Circus bareback rider Pierre Radier meets small town woman Joanna Ryan, and they have a brief affair, which leaves her pregnant. Although Pierre offers to marry her, Joanne refuses, preferring to marry a more stable local man who knows about her pregnancy. Pierre has long wanted to leave the circus, even though his alcoholic mother, Madame Azais, advises against it. When Henry Mueller, the circus handyman, asks Pierre to join him in a business venture, Azais refuses to lend Pierre the necessary money. While secretly visiting Joanna after the birth of her baby son, Pierre meets Leah Ernst, a wealthy widow who falls in love with him. Pierre begins an affair with Leah and she lends him the money to open a bicycle shop with Mueller. The shop is a big success, but Mueller is not satisfied. He designs an automobile, which catches the eye of financier Homer Flint. To cement the deal, Pierre marries Flint's daughter Hazel after ending his relationship with Leah. He also becomes an American citizen, changing his name to Paul Rader. Together Flint and Pierre start an auto factory. When he is playing golf one day, Pierre meets his son, Pierre Croy, who is now a young boy. He asks Joanna to allow him to adopt the boy, but she refuses, convinced he will have a better life on the farm. Pierre continues to amass money, and when World War I starts, he diversifies into munitions. He sends his son gifts, and when Pierre, Jr. is old enough, sends him away to school. His marriage to Hazel is not a success, and soon he is spending his time in New York visiting with his son and a series of attractive women. Carried away with a sense of his own importance and invulnerability, Pierre invests his and Flint's money in stocks. After his son is killed driving the car he gave him for his birthday, Pierre's life starts to fall apart. Hazel discovers Pierre, Jr's parentage, and finally ends her marriage. Pierre loses all his money in stock speculation as well as that of his father-in-law. Joanna blames Pierre for the death of her oldest son. Penniless and friendless, Pierre seeks out his mother, who is now making a living as a fortune-teller. They plan to return to Europe, where Pierre hopes he will be worthy of her.
