Jess and his sons Mark and Paul are at war with the people who live in the valley below their cabin. Abner is the leader of the neophytes and is as bent on ruling the valley as Jess is. Abner's friend Caleb is the shaman of the people. Caleb's daughter Ruth is fair skinned and the object of Mark's desire. Abner has a dream in which he sees himself building a machine that will be able to destroy the cabin. He commands the men he leads to build the machine. Abner's machine hurls stones at the cabin as Jess fires bullets as the men who work the machine. Many of them are killed but those who are left persevere. Mark is discovered in the valley and he fears for his life. Abner recruits him to help with the machine as they continue to throw stones at the cabin. As the battle between Abner's forces and Jess and Paul rages, Mark is able to accompany Ruth to try to escape the utter destruction that he thinks has to be the end result of the battle.