It is usually thought that the framework of the story with marriages, murders and people is reliable but that the rest is a made up story.
The focus of the story is Guðrun, who was famed for her beauty and her intelligence. Two foster brothers lust after her - Kjartan Ólavsson and Bolli Tórleiksson. Guðrun loves Kjartan but through a series of lies Bolli manages to get hold of her. The foster brothers become enemies and in the end Bolli kills Kjartan. Later in the story Bolli meets the same destiny as his misdeed is avenged.
The story is about models of reverence; about the destructive and untamed force of love and the mercilessness of destiny. It has been described as “one of the greatest tragedies of love in Nordic literature, portrayed with a deep psychological insight and literary skill.”