During a feud between two warring clans in medieval Iceland, Hagbard and his two brothers ride forth to avenge the death of their father, King Hamund, at the hand of King Sigvor. On a neutral beach, a daylong battle ensues between Hamund's sons and Sigvor's three sons. The fight is so evenly matched that Sigvor finally orders the young men to stop fighting and offers Hamund's sons his friendship and hospitality. When everyone rides back to Sigvor's household and the women help prepare the men for their sauna, a bond develops between Hagbard and Sigvor's daughter, Signe. At the feast that night, Hildegisl, a jealous suitor of Signe, notices the burgeoning romance and bribes King Sigvor's councilor, Bolvis, into inciting Sigvor's sons, who break the truce and kill Hagbard's two brothers. Hagbard returns from a hunting trip, learns of the death of his brothers, and kills Sigvor's three sons; he then flees to the home of his mother. Though Sigvor brands him an outlaw and orders his capture, Hagbard cannot bear to be away from his beloved. Disguising himself as a woman in a red mantle, he sneaks into Signe's bedchamber, and they consummate their love. A maid betrays them, and Hagbard is captured and sentenced to die. When Hagbard is taken to be hanged, he aids Signe in fulfilling her vow not to outlive his death by giving her a signal; he requests that first his red mantle be hoisted, so that he may "see what a hanging looks like." Signe sees this sign from her window, and, presuming Hagbard dead, she sets fire to her room and kills herself. Assured by the sight of the flames that the vow has been fulfilled, Hagbard himself places the noose around his neck and kicks away the supporting stool--thus joining his beloved Signe in death.
