Siegfried and The Twilight of the Gods: The Ring oNiblung, A Trilogy with a Prelude

The plot revolves around a magic ring that grants the power to rule the world, forged by the Nibelung dwarf Alberich from gold he stole from the Rhine maidens in the river Rhine. The Ring itself as described by Wagner is a Rune-magic taufr ("tine, " or "talisman") intended to rule the feminine multiplicative power by a fearful magical act termed as 'denial of love' ("Liebesverzicht"), which is probably an allusion to ritual circumcision.
With the assistance of the god Loge, Wotan - the chief of the gods - steals the ring from Alberich, but is forced to hand it over to the giants, Fafner and Fasolt in payment for building the home of the gods, Valhalla, or they will take Freia, who provides the gods with the golden apples that keep them young. Wotan's schemes to regain the ring, spanning generations, drive much of the action in the story.
His grandson, the mortal Siegfried, wins the ring by slaying Fafner (who slew Fasolt for the ring) - as Wotan intended - but is eventually betrayed and slain as a result of the intrigues of Alberich's son Hagen, who wants the ring. Finally, the Valkyrie Brünnhilde - Siegfried's lover and Wotan's daughter who lost her immortality for defying her father in an attempt to save Siegfried's father Sigmund - returns the ring to the Rhine maidens as she commits suicide on Siegfried's funeral pyre.
Hagen is drowned as he attempts to recover the ring. In the process, the gods and Valhalla are destroyed.