Hilda, the younger sister of Gunther, king of the Burgundians, loves the hero Sigurd, despite that she was expected to be given to Attila himself as a bride. At the instigation of her nurse (Uta) she gives Sigurd a magic potion which brings him to her feet. Sigurd, Gunther and Hagen then swear fealty to each other and set off to Iceland, where Brunehild lies asleep upon a lofty rock, surrounded by a circle of fire and some supernatural beings. There, Sigurd, to earn the hand of Hilda, must overcome those monsters and passes through the flames and wins Brunehild for Gunther. His face is closely hidden by his visor, and Brunehild in all innocence accepts Gunther as her saviour, and gives herself to him. The secret is afterwards disclosed by Hilda in a fit of jealous rage, whereupon Brunehild releases Sigurd from the enchantment of the potion. He recognises her as the bride ordained for him by the gods, and they sing together a passionate love duet, but before he can taste his new-found happiness he is treacherously slain by Gunther during hunting. His body is brought back to the palace and Brunehild mounts the funeral pyre. Powerful apotheosis ends the opera when spirits of Sigurd and Brunehild ascend to paradise, and soldiers of Attila are seen walking over corpses of Burgundians.