The original plot (in the novels) follows Arn Magnusson who is part of the powerful Folkung dynasty in the middle 12th century. He grows up in a monastery belonging to Cistercians. He is trained in archery, swordsmanship and horsemanship by a former Knights Templar who is serving a penance as a monk for a sin. When he leaves the monastery and returns to his family, he is soon pulled into the power struggle between the powerful families, all fighting for the crown of the young nation that is to become the Kingdom of Sweden. He helps his friend Knut Eriksson to kill the old king Karl Sverkersson.