Saccard and Gunderman are rival Paris bankers. Saccard sees an opportunity to rescue his failing bank, Banque Universelle, by financing the solo transatlantic flight of Jacques Hamelin, a pioneering aviator. Saccard intends to capitalise on his popularity to set up a colonial business project in Guyane and to seduce Hamelin's wife Line in his absence. When a rumour circulates that Hamelin has crashed, Saccard exploits the false reports to manipulate shares at the Bourse. Gunderman disapproves of Saccard and his methods and has secretly bought shares in his bank to as a weapon. Baroness Sandorf, a former lover of Saccard, acts as a spy to assist Gunderman's interests and advance her own.