Prelude. On the Valkyrie's rock, by night, sit the Nornir (Fates) weaving their rope of runes. It breaks and they disappear, knowing that the End of the gods is at hand. At day-dawn Siegfried rises to part from his beloved Brynhildr and go to fresh exploits. At parting he gives her his famous Ring and she gives him her horse in return.<br><br>Act I. He comes to the Hall of the Gibichungs on the Rhine, where live the king Gunther, his sister Gudrun and their half-brother Hagen, the son of Alberic. These, for their own purposes, give Siegfried a magic draught of forgetfulness. He swears brotherhood to Gunther, forgets Brynhildr, falls in love with Gudrun and, in return for her hand, consents to go through the fire and fetch Brynhildr as a wife for Gunther, who cannot perform the feat himself.<br><br>Brynhildr, awaiting Siegfried's return, is visited by her sister Valtrauta, who implores her to restore the fatal Ring to the Rhine, as the only means of saving the gods, who are now expecting their doom; but Brynhildr, being an outcast from Valhalla, regards her love-pledge as of more value than all the gods, and refuses: Valtrauta flies away in despair, Siegfried, taking Gunther's shape, by virtue of the Tarnhelm, appears to the horror-stricken Brynhildr and demands a husband's rights. She resists fiercely, but is conquered by his tearing from her finger the Ring, which gave her supernatural strength. Siegfried weds her, but lays his sword between them, as his oath to Gunther demands.<br><br>Act II. Alberic visits his son Hagen in a dream and bids him strive to kill Siegfried and obtain the Ring. Siegfried, followed later by Gunther and Brynhildr, returns to the Gibichungs' Hall and all the vassals are summoned to rejoice at the double wedding. Brynhildr, being brought face to face with Siegfried in his own shape, perceives the Ring upon his finger and proclaims to all that she has been betrayed. Explanations, purposely confused by Hagen, only make it appear that Siegfried has failed in his oath to Gunther, whereupon Hagen persuades Brynhildr and Gunther to consent to his murder.