According to the Sioux legend, a large wooden mast supports our world, above the abyss. And with every sin of Man, Grand Father Castor eats a little more the mast, precipitating our world to its fall. When Man has sinned too much, our civilization will be condemned. For the members of the Prairie reserve, this moment has arrived. Agent Dashiell Bad Horse finally holds the elements that will allow the FBI to bring down Red Crow: the witness of a cold blood murder perpetrated by the head of the reserve.