Wotan is giving orders to his valkyrie daughter Bruennhilde: she is to protect Siegmund in the fight that will come soon. Just then Fricka arrives and starts to complain: she, as the guardian of the wedlock, is furious at Wotan's latest stunt. She was alarmed by Hunding's prayers to her, but Wotan says he does not honor Hunding's marriage since it was against Sieglinde's will. Now Fricka says the trouble is not only that but - she asks - when has anyone heard of twin-born lovers! Wotan answers abruptly: you are hearing of it now. But Fricka insists that it is the gods' status and honour that is at stake: should they lose the mortals' respect, they would lose their power.
Not even Wotan's explanations can change her mind: as Wotan calls Siegmund a "free hero", she quite rightly points out that Siegmund not free nor independent at all [since it was Wotan - posing as "Volsa" - who brought him up, and led him to the "Wotan Sword" (as it is called by Mime in the opera)] and she demands that Wotan withdraw all protection and even the magic sword from Siegmund - and finally makes Wotan give his promise of that.
Fricka leaves as Bruennhilde enters and finds her father looking gloomy. Wotan tells her his tale: how Loge tricked him into dishonest treties concealing evil, how they stole the Ring and how he was warned by Erda. Later Wotan visited her again "in the bowels of the earth" and overpowered her with the magic of love. Erda gave him information but as a price bore him Bruennhilde the Valkyrie [though the other 8 Valkyries are her "sisters" and quite equal in status and powers, they may have a different mother - this would explain Bruennhilde being Wotan's favorite child]. Wotan sent the valkyries to collect perished brave heroes into the halls of Valhalla to avert the horrible end Erda foretold. Alberich's army could not beat Wotan's heroes, but if Alberich regained the Ring, he could turn Wotan's heroes against him. Fafner is guarding the Ring now, but Wotan's own treaties prevent him from attacking Fafner directly. Thus, the only possible solution for him is to let a free hero kill Fafner - Siegmund was to be this hero, but as Fricka remarked, Siegmund was everything but free. Wotan has no idea what to do now. He even knows the end is near for Erda said that when Alberich has a son, the end will come soon: now he has learned Alberich has bought a woman with gold and that woman is now pregnant with Alberich's child.
Wotan orders Bruennhilde to protect Hunding instead of Siegmund, but Bruennhilde - feeling as compassionate toward Siegmund as Wotan himself - refuses. Wotan is angered by this: he furiously orders Bruennhilde to ensure that Siegmund dies. Bruennhilde can only obey.
Siegmund and Sieglinde are desperately fleeing Hunding and his kinsmen who are hunting them with dogs. Sieglinde gets hysterical and faints. Then Bruennhilde appears and announces to Siegmund that only those doomed to die may see her - he is to follow her to Valhalla. But as he learns he will not find Sieglinde in Valhalla, Siegmund refuses Bruennhilde's promises. He decides he'll rather kill himself and Sieglinde with one swift blow than let Hunding get them. Bruennhilde is so moved by his courage that she decides to rebel against Wotan's orders and protect Siegmund.
When Sieglinde awakens, Siegmund has already left to face Hunding: she can hear their voices but cannot see them. Hunding and Siegmund fight, after a few insults. As they fight, Bruennhilde appears, holding a shield above Siegmund and tells him trust his sword. But then Wotan appears, in a red storm cloud and breaks Nothung into pieces with his spear. Hunding finishes Siegmund off easily, Bruennhilde flees with Sieglinde on her horse's back.
Wotan gazes thoughtfully Siegmund's corpse and then turns to Hunding who is gloating over his victory. He gives Hunding one contemptuous gesture and Hunding falls down dead. Then he turns to chase Bruennhilde, the rebel, who dared disobey his order and leaves with thunder and lightning.
Next:Die Walküre, Act III