Beneath the flowing waters of the Rhine river, the Rhinenymphs, Woglinde and Wellgunde, frolic and play instead of keeping a watchful eye on the precious Rhinegold.
Up from the depths of the earth clambers Alberich of the Nibelungs - a race of cunning subterranean dwarves. Alberich eyes the nymphs lustfully, but they nimbly elude his amorous embrace. Just then, the sleeping gold awakes and the nymphs inform Alberich that anyone who can forge a Ring from the gold will gain ultimate power, but they must first renounce love. To their surprise, Alberich does just that, and disappears into the earth with the stolen Rhinegold.
Wotan, the ruler of the gods, wakes to see the sun rising over Valhalla, a magnificent heavenly castle which has been constructed for him by the builder-giants Fasolt and Fafner. To Wotan's chagrin, his wife Fricka reminds him that in order to compensate the giants for their labor, he had promised to give them Freia the goddess of youth. When the giants come to collect on their bargain, Wotan suggests an alternative payment. He offers to steal Alberich's Rhinegold for them.
Wotan, in disguise, ventures to Nibelheim, where Alberich has forged a Ring from the gold and made himself ruler of the Nibelungs, and forced his brother Mime the Nibelung to create a magical Tarnhelm from the gold which allows Alberich to shape change at will.
Wotan tricks Alberich into becoming a toad so that he can trap him and snatch the Ring from the helpless amphibian. Alberich, enraged, places a horrible curse upon the Ring: Anyone who possesses it will die.
Returning to Valhalla, Wotan gives the Ring to the giants who immediately fall to quarreling. Fafner slays his brother and makes off with the Ring the gold and the Tarnhelm. Wotan contemplates the evil he has unleashed, as the Rhinenymphs lament the loss of their gold.
The battle-weary Siegmund takes shelter in a road-side hut, little suspecting that it is the home of Hunding - of clan Hunding, his arch enemies.
Hunding's wife, Sieglinda, offers Siegmund refuge for she feels an inexplicable attraction to the stranger. Unbeknownst to the two, they are fraternal twins, both children of Wotan.
Hunding returns from battle to find his foe, recuperating in his own home. Hospitality demands that he let Siegmund stay the night, but he promises to slay the weaponless Siegmund in the morning.
Sieglinda shows Siegmund a sword which, many years before, Wotan had left embedded in the trunk of a tree growing in Hunding's hut. Siegmund pulls out the sword and runs away with Sieglinda.
Fricka, goddess of marriage vows, demands that Wotan side with Hunding in the impending battle. Although Siegmund is an integral part of Wotan's plan to recover the lost Ring, he reluctantly obeys Fricka and sends Brunnhilde, his favorite Valkyrie to protect Hunding. Brunnhilde, however, rebels, and Wotan is forced to intervene, slaying Siegmund himself. During the battle, Brunnhilde rescues Sieglinda and spirits her away to a safe hiding place in the woods.
Wotan punishes Brunnhilde's disobedience by putting her to sleep on a mountaintop surrounded by a ring of magic fire which only the most fearless hero can penetrate.
Mime, the Nibelung, and brother of Alberich, has found Sieglinda in the forest and has brought up the child which she died in giving birth to, knowing that he is destined to slay Fafner and gain the Ring.
Wotan, in disguise, prophesies Mime's death at the hands of Siegfried.
Mime induces Siegfried - under pretext of teaching him how to fear, a skill which the youth is curious to learn - to accompany him to a distant part of the forest where Fafner in the shape of a huge dragon, guards the Nibelung treasures, including the ring. Siegfried kills the dragon, but upon accidentally tasting its blood, is enabled to understand the speech of birds. They tell him how Mime means to poison him to obtain the treasure; accordingly he kills the traitor. The bird further tells him of a fair sleeping bride surrounded by fire, and flies before him to show the way to her resting place.
Siegfried plunges through the fire, finds the Valkyrie, wakes her, woos her and wins her.
(Twilight of the Gods)
On the Valkyrie's rock, sit the three Norns (Fates) inscribing history upon the pages of the Book of Time. The binding cracks and the book is torn asunder, and they disappear, knowing that the end of the gods is at hand.
At dawn, Seigfried departs from his beloved Brunnhilde to go on fresh exploits.
He comes to the Hall of the Gibichungs on the Rhine, where live the King Gunther, his sister Gutrune and their half-brother Hagen, son of Alberich. These, for their own purposes, give Siegfried a magic draught of forgetfulness. He forgets Brunnhilde, falls in love with Gutrune and, in return for her hand, consents to go through the fire and fetch Brunnhilde as a wife for Gunther, who cannot perform the feat himself.
Brunnhilde, awaiting Siegfried's return, is visited by her sister Waltraute, 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 Brunnhilde, an outcast from Valhalla, values her love-pledge to Siegfried more than all the gods, and refuses. Siegfried, taking Gunther's shape, by virtue of the Tarnhelm, appears to the horror-stricken Brunnhilde 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. As Gunther, Siegfried weds her.
Alberich visits his son Hagen in a dream and urges him to kill Siegfried and obtain the Ring. Siegfried, followed later by Gunther and Brunnhilde, returns to the Gibichung's Hall and all the vassals are summoned to rejoice at the double wedding. Brunnhilde, being brought face to face with Siegfried in his own shape, sees 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 broken his promise to Gunther, whereupon Hagen persuades Brunnhilde and Gunther to consent to his murder.
Siegfried, Hagen and Gunther go on a hunting expedition, and while they are carousing and Siegfried is telling the story of his life, Hagen spears him in the back and kills him.
The body is brought to the Hall and Hagen kills Gunther in a struggle for the Ring. The despairing Brunnhilde orders a funeral pile to be built by the Rhine. This she mounts with the dead Siegfried and both are consumed, when the river rises and the Nymphs regain at last their Ring from the ashes, Hagen being drowned in attempting to seize it. A ruddy glare is seen in the sky: the Dusk of the Gods is at hand, and Valhalla is seen burning with all its array of heroes and gods.