A rocky cave in the forest.
Fruit of the love between Siegmund and Sieglinde, Siegfried was entrusted when still a baby, by his dying mother, to the care of the dwarf Mime, the Nibelung brother of Alberich who lives in a forge in the depths of the forest. Mime raised the child, not out of pity or love, but in order to exploit his courage in the future and to gain possession of the Nibelungs’ ring and treasure.
These are guarded in an impenetrable cave, by the giant Fafner, now transformed into a monstrous dragon. Siegfried himself feels only contempt for his guardian whereas the latter demands full recognition for the care and attention he has lavished on the boy. Now that Siegfried has reached manhood, however, Mime can no longer hide the truth of his origins from him. So he is forced to reveal the name of Siegfried’s mother and to hand over the fragments of Notung, the invincible sword that belonged to his father. Siegfried lights up with enthusiasm and orders Mime to mend the weapon at once.
Left alone, the dwarf sets to work. But he toils in vain, for on the threshold of the smithy appears a mysterious wanderer, whose disguise conceals the god Wotan. After a long conversation, the god predicts that Notung shall be forged only by a fearless man. Upon his return, Siegfried, who fears nothing, tempers the magic sword. Now he can confront the grim Fafner. Meanwhile Mime prepares a sleeping draught with which to get rid of Siegfried as soon as he has slain the dragon and reconquered the Nibelungs’ ring and treasures.
In the depths of the forest.
Near Fafner’s cave, the wanderer comes upon Alberich, who has never abandoned hope of regaining possession of the lost treasure. The wanderer predicts Siegfried’s victory over the dragon and puts him on his guard against the real intentions of Mime. At daybreak, while Siegfried listens to the voices of the awakening forest, Fafner appears at the entrance to the cave. The dragon hurts itself at Siegfried, who pierces it with his sword.
A drop of Fafner’s blood falls on Siegfried’s hand and when he licks it he finds he can understand the song of the birds. In this way he learns of the existence of the treasure and of Mime’s true intentions. Having quarrelled violently with Alberich, Mime now approaches to offer Siegfried the potion. But the young man refuses it and kills the dwarf. Having got possession of the magic ring, he sets oft for the Valkyries’ hilltop where, surrounded by huge flames, Brünnhilde lies in a deep sleep from which only a fearless hero can rouse her.
A crevice at the foot of a rocky mountain.
After receiving evasive replies from Erda, goddess of the earth, concerning the fate of the race of gods, Wotan clashes with Siegfried. Aware that the gods would disappear if the young man were to succeed in rescuing Brünnhilde,Wotan attempts to bar his way. But Siegfried pushes past and mashes Wotan’s spear with his sword. Striding through the flames, he reaches Brünnhilde and kisses her.When the Valkyrie recognizes Siegfried as the hero long awaited since she fell into her deep sleep, she comes back to life. For an instant she seems gripped by fear of losing her divine condition. But then, reassured by Siegfried’s words, Brünnhilde yields to his embrace.