Hagen has fallen asleep. His father, Alberich, appears in a dream vision. He tells Hagen that he must oppose Wotan's kin and gain the Ring no matter what price. He also says that the Rhinemaidens must not get the Ring or all is lost - and that Bruennhilde might be wise enough to do that. As Alberich gets Hagen's promise, he disappears and Hagen wakes up.
Just then Siegfried appears, using the Tarnhelm's power of teleportation. He speeds to Gutrune, telling her that she can now marry Siegfried: he has completed his part of the bargain.
Hagen blows into a cowhorn, summoning the Gibich vassals, who think there is an attack or some other danger. This is, however, only a practical joke: he tells the alarmed vassals that there is no danger and they should now prepare a great marriage feast. The vassals love Hagen's joke.
As the crowd watches, Bruennhilde and Gunther come from a boat. Bruennhilde is shocked, seeing Siegfried and Gutrune together. Then she notices the Ring on Siegfried's finger and says it was Siegfried who took the Ring from her. Siegfried is confused: he can now remember slaying a Dragon and thus winning the Ring. Hagen suggests to Bruennhilde that Siegfried has played some trick. Bruennhilde screams: trickery! treachery! The crowd is getting nervous. She even claims that Siegfried forced delight from her, at which Siegfried decides to swear a new oath that he has spoken true. Hagen offers his spear for the oath. Siegfried swears: if I have sworn falsely, let yours be the blade that pierces me. Suddenly, Bruennhilde also places her hand on the spear and blesses the blade for this purpose, for, she says, falsely has Siegfried sworn indeed. Siegfried feels a bit uneasy whispers to Gunther that maybe the Tarnhelm hid his features only partially and instructs Gunther that he should let Bruennhilde be in peace for some time so that she can learn to accept her fate.
Later, Bruennhilde, Hagen and Gunther are together. Bruennhilde wonders what has happened to Siegfried - what devil's trickery has made him betray her? Hagen offers to avenge her on Siegfried, but Bruennhilde doubts his combat prowess: a single flicker from Siegfried's eyes would suffice to make Hagen's courage falter. Surely, asks Hagen, he would still be vulnerable to his spear because of the false oath he swore on it? Bruennhilde says that she has protected Siegfried with magic which makes him invulnerable to any weapon - only his back she spared protection as she knew Siegfried would never turn and run from any combat. There shall my spear strike, declares Hagen. Gunther is desperate: the events have put him into a terrible shame. Hagen's answer is that only one thing can restore his honour now: Siegfried's death. Gunther falls silent and hesitates, but Hagen makes him come around with a hint of the all-powerful Ring which Siegfried is wearing. Bruennhilde, Hagen and Gunther decide that Siegfried shall die. Aside, Hagen tells Alberich to summon the Nibelungs to serve him once more: the hour of their dominion is at hand.
Next:Götterdämmerung, Act III