ACT I. As a storm rages, Siegmund, pursued by enemies, stumbles exhausted into an unfamiliar house. Sieglinde finds him lying by the hearth, and the two feel an immediate attraction. But they are soon interrupted by Sieglinde’s husband, Hunding, who asks the stranger who he is. Calling himself “Woeful,” Siegmund tells of a disaster-filled life (“Friedmund darf ich nicht heissen”), only to learn that Hunding is a kinsman of his foes. Hunding, before retiring, tells his guest they will fight to the death in the morning.
Left alone, Siegmund calls on his father, Wälse, for the sword he once promised him. Sieglinde reappears, having given Hunding a sleeping potion. She tells of her wedding, at which a one-eyed stranger thrust into a tree a sword that has since resisted every effort to pull it out (“Der Männer Sippe”). Sieglinde confesses her unhappiness to Siegmund. He embraces her and vows to free her from her forced marriage to Hunding. As moonlight floods the room, Siegmund compares their feeling to the marriage of love and spring (“Winterstürme”). Sieglinde hails him as “Spring” (“Du bist der Lenz”) but asks if his father was really “Wolf,” as he said earlier. When Siegmund gives his father’s name as Wälse instead, Sieglinde recognizes him as Siegmund, her twin brother. He pulls the sword from the tree and claims Sieglinde as his bride, rejoicing in the union of the Wälsungs.
ACT II. High in the mountains, Wotan, leader of the gods, tells his warrior daughter, the Valkyrie Brünnhilde, that she must defend his mortal son Siegmund in his upcoming battle with Hunding. Leaving joyfully to do his bidding (“Hojotoho!”), the Valkyrie passes Fricka, Wotan’s wife and the goddess of marriage. Fricka insists that Wotan must defend Hunding’s marriage rights against Siegmund. She ignores his argument that Siegmund could save the gods by winning back the Ring from the dragon Fafner. When Wotan realizes he is caught in his own trap—his power will leave him if he does not enforce the law—he agrees to his wife’s demands. After Fricka has left in triumph, the frustrated god tells the returning Brünnhilde about the theft of the gold and Alberich’s curse on it (“Als junger Liebe”). Brünnhilde is shocked to hear her father, his plans in ruins, order her to fight for Hunding. Then, alone in the darkness, she withdraws as Siegmund and Sieglinde approach.
Siegmund comforts his distraught bride, and watches over her when she falls asleep. Brünnhilde appears to him as if in a vision, telling him he will soon go to Valhalla (“Siegmund! Sieh auf mich!”). He tells her he will not leave Sieglinde and threatens to kill himself and his bride if his sword has no power against Hunding. Brünnhilde, moved, decides to defy Wotan and help him. She vanishes. Siegmund bids farewell to Sieglinde when he hears the approaching Hunding’s challenge. When Siegmund is about to win, however, Wotan appears and shatters his sword, leaving him to be killed by Hunding. Brünnhilde escapes with Sieglinde and the broken sword. Wotan contemptuously fells Hunding with a wave of his hand and leaves to punish Brünnhilde for her disobedience.
ACT III. On the Valkyries’ Rock, Brünnhilde’s eight warrior sisters—who have gathered there briefly, bearing slain heroes to Valhalla— are surprised to see her enter with Sieglinde. When they hear she is fleeing Wotan’s wrath, they are afraid to hide her. Sieglinde is numb with despair until Brünnhilde tells her she bears Siegmund’s child. Eager to be saved, she receives the pieces of the sword from Brünnhilde and thanks her rescuer, then rushes off into the forest to hide from Wotan. When the god appears, he sentences Brünnhilde to become a mortal woman, silencing her sisters’ objections by threatening to do the same to them. Left alone with her father, Brünnhilde pleads that in disobeying his orders she was really doing what he wished (“War es so schmählich”). Wotan will not give in: she must lie in sleep, a prize for any man who finds her. But as his anger abates she asks the favor of being surrounded in sleep by a wall of fire that only the bravest hero can pierce. Both sense this hero must be the child that Sieglinde will bear. Sadly renouncing his daughter (“Leb’ wohl”), Wotan kisses Brünnhilde’s eyes with sleep and mortality before summoning Loge, the god of fire, to encircle the rock. As flames spring up, the departing Wotan invokes a spell forbidding the rock to anyone who fears his spear (Fire Music).