After an adventurous life, Patrick has settled in the Camargue and bought a manade where he raises bulls, while the "riziers" gradually invade and transform the land. On the very day the bulls are being branded, Patrick sees Robert, a long-lost comrade just out of prison. He takes him in and asks for nothing, despite the general hostility. In fact, Robert begins by poaching young Paco, son of the gardian-chef, by offering to rob a bank; then he covets his friend's almost-fiancée, Zeffa; finally, he organizes a devastating expedition against the rice farmers, in short, he behaves like a real "dog in a poke", sowing discord and brawl everywhere.

In the south of France, in a vast plain region called the Camargue, lives White Mane, a magnificent stallion and the leader of a herd of wild horses too proud to let themselves be broken by humans. Only Folco, a young fisherman, manages to tame him. A strong friendship grows between the boy and the horse, as the two go looking for the freedom that the world of men won’t allow them.