By Richard Wagner
Three Norns, daughters of Erda, recount their knowledge again: Wotan has felled the withered World ash-tree, from which he once cut his spear, and had it taken to the pyre around Valhalla. Here he awaits his end - his power has expired because Siegfried has destroyed the god's spear.
But the rope with which the Norns want to hold everything together snaps. Their wisdom is at an end.
Siegfried and Brünnhilde appear untroubled by the imminent downfall and delight in the rapture of their love. Brünnhilde sends her hero to seek new adventures. Siegfried leaves her the Ring as a love token. Brünnhilde too falls under the spell of the cursed object.
The Gibichungs Gunther and Gutrune learn from their halfbrother Hagen, Alberich's son, of the most beautiful woman and the strongest man in the world: Brünnhilde and Siegfried. Winning them as husband and wife could considerably enhance the fame of the siblings for their standing suffers from the fact that they are unmarried. Siegfried’s journey on the Rhine takes him to the Hall of the Gibichungs. Only he could pass through the flames protecting Brünnhilde and win her for Gunther; but to fall in love with Gutrune, he first has to forget all the other women he has known. A drugged potion makes Siegfried forget and inflames his love for Gutrune. To help her brother find a worthy wife, he offers to capture Brünnhilde for Gunther. Having sworn to be blood brothers, Siegfried and Gunther make their way to Brünnhilde. She is waiting longingly for her hero to return when her sister Waltraute unexpectedly appears. Acting against Wotan who has expressly forbidden her to come, she urges her sister to return the Ring to the Rhinemaidens. Only this can avert the destruction of the gods but Brünnhilde refuses to surrender Siegfried's love token.
Her solitude is disturbed once more: Siegfried, wearing the Tarnhelm and in the guise of Gunther, tears the Ring from Brünnhilde’s finger as symbol of marriage with the Gibichung.
Drowsing, Hagen is standing guard when his father Alberich appears to him. In loyalty to his father, Hagen should win back the Ring.
Siegfried returns to the Hall of the Gibichung where Hagen orders his men to prepare for the double wedding. Accompanied by Gunther, Brünnhilde encounters Gutrune and Siegfried. In despair, she realises that Siegfried does not recognise her but when she notices the Ring on his finger, she sees through the treachery. She accuses Siegfried who for his part swears a false oath on Hagen's spear of never having loved any other woman than Gutrune. Brünnhilde's love has turned to hate. She wants revenge. Hagen, Gunther and Brünnhilde together plan Siegfrieds death.
The Rhinemaidens' game has lost its objective. Only when Siegfried comes to them does it gain new energy. They warn him to return the Ring but the curse which rests on the gold does not deter the fearless Siegfried. The Rhinemaidens too can only leave him with the prophesy of doom.
Hagen and Gunther and their huntsmen meet Siegfried, now alone. Unsuspecting, Siegfried agrees when Hagen asks him to relate his adventures. He speaks of Mime, his fight with Fafner, the words of the bird and finally, prompted by a potion given to him by Hagen to restore his memory, also of his love for Brünnhilde. He is found guilty of false oath, and Hagen kills him with his spear on which this oath was sworn. Siegfried’s last words are for Brünnhilde.
When Siegfried's body is carried back to Gutrune, she accuses her brother of murder but Hagen confesses to the deed. In a quarrel over the Ring, he kills Gunther but Brünnhilde now realises that she has been used as a pawn in the game. She alone can take possession of Siegfried's Ring. By dying with him, she wishes to save his honour and thus becomes the instrument to complete Wotan's final plan. She returns the Ring to the Rhinemaidens and kindles a fire, to which both Valhalla and the gods finally fall victim. Hagen's last attempt to seize the Ring fails. The earth seems freed from the curse of the gold.