The Nibelungenlied opens with the youth and heroic exploits of Siegfried, a prince of Netherland who slays a dragon, acquires the vast Nibelungen hoard, and bathes in dragon blood to render himself invulnerable. Drawn to Worms by the fame of the Burgundian princess Kriemhild, Siegfried assists King Gunther in his impossible courtship of the fierce Isenland queen Brunhild. Through feats of preternatural strength and the use of a magical tarnkappe, Siegfried secures Brunhild as Gunther's bride, paving the way for his own marriage to Kriemhild.
Tensions escalate when Brunhild, suspicious of Siegfried's status as a supposed vassal, demands submission from Kriemhild. During a bitter confrontation at the minster door, Kriemhild humiliates Brunhild by revealing the truth of the wooing deception and displaying the ring and girdle Siegfried had taken from her. Stung by this public disgrace, Brunhild demands vengeance, enlisting Gunther and his loyal retainer Hagen in a dark conspiracy.
Hagen tricks Kriemhild into revealing Siegfried's single vulnerability—a linden leaf that fell on his back during his bath in dragon blood. Under the guise of a royal hunt, Hagen betrays and murders Siegfried, casting a heavy shadow over the Burgundian court. Kriemhild is consumed by grief, and her sorrow slowly hardens into an unrelenting desire for retribution against those who orchestrated the assassination.
Years later, Kriemhild marries King Etzel of the Huns, biding her time before inviting her brothers to visit her distant court. Despite ominous warnings, Gunther, Hagen, and the Burgundian host journey to Etzel's realm, where an escalating series of provocations erupts into a cataclysmic battle. The epic culminates in relentless slaughter within Etzel's burning hall, leaving the major figures dead amid the ruins of their ancient loyalties.