Vernon Felps and his wife Annabelle bought their land from the government and came to settle in the plains of the West, in Cow Gulch exactly. These settlers from the East are farmers. But the cattle of a man named Cass Casey crosses Vernon's land, ruining everything on his way. The cohabitation between the farmer and the "cattle king" (rich breeder) is a delicate announcement. In order to preserve his land, Vernon decides to close them with barbed wire, which is considered by the breeders as a personal insult... The war is declared between breeders and farmers, but Lucky Luke, to whom Vernon asked for help, will be able to reconcile all this small world. The plains of the West are big enough for all!