In the decades between Die Walküre and Siegfried, the world of San Francisco Opera’s Ring has crumbled. Brünnhilde’s rock lies in ruins. Stumps and barren, charred trunks form the forest. Mime and Siegfried usually live in a hut in the woods; here, they inhabit a broken trailer on a trash heap. Their quest to find Fafner takes them to an abandoned warehouse, where the survivalist Alberich hunkers down with night-vision goggles and homemade bombs. Siegfried must battle a huge trash compactor to claim the Niebelung gold. (A minor textual quibble: Fafner is his usual giant self within this machine, which goes against the libretto’s assertion that he used the Tarnhelm to change his shape.)

If this all sounds rather ugly, it is... but it’s also enormously impressive. The technical demands of the Ring’s epic story have been well met this entire cycle, but Siegfried surpasses its prequels. The use of steam effects, a glowing orange screen, and many prop swords (as well as Siegfried’s deft handling of all the latter) make for a wonderfully detailed and realistic forging scene. Siegfried doesn’t just stab the dragon-machine; they engage in a pitched battle where it shoots smoke, and sparks fly whenever Siegfried’s sword scrapes the machine’s shell. (Appropriately, he defeats it by stabbing its electronic control box.) When Siegfried breaks Wotan’s spear (again, after a struggle), there is a blinding flash as the whole stage changes color and both combatants are thrown apart and to the ground.

Special effects don’t make a great opera (though they don’t hurt!); music and drama do. Francesca Zambello’s dramatic take is as grim as her setting. Siegfried lacks a single redeeming characteristic. He is not just a petulant teenager in spiked hair mocking Mime’s repetitive speeches and twitching face. He is also a sociopath who drowns Mime to make him talk, and who is tempted to light his victims’ corpses on fire. (Only the Forest Bird’s frantic interference stops him.) Daniel Brenna acted the role with frightening credibility and sang in a rough, resounding tenor. His voice didn’t always carry clearly above the music – the forging song, for instance, felt underpowered – but that is partly because the staging didn’t sufficiently account for the acoustic challenges of the house.

David Cangelosi’s Mime was pathetic and despicable, a cringing coward who hid, trembling, behind his own apron when he discovered Wotan’s identity. Cangelosi threw himself into the part with infectious glee, dancing and turning cartwheels when he thought his schemes were succeeding. Conversational delivery of his text and bone-dry low notes made for an unusual, expressive sound. As his brother Alberich, Falk Struckmann conveyed an air of dark menace, delivering thudding hammer blows with his voice. Greer Grimsley’s Wotan-as-Wanderer seemed perpetually on the verge of a nervous breakdown, with his hollow laughter and self-destructive choices. Without being huge or heroic, Grimsley’s full sound had a steel core the cut through the orchestra.

After two hours of nothing but men’s voices, Stacey Tappan’s bright, chirpy Forest Bird in Act 2 was a welcome change. This bird was onstage and very human – a girl in multicolored (c. 1960s) trousers who was intrigued by Siegfried and decided to help him. The concept fit Zambello’s forest-less world, even if the character wasn’t quite coherent. (Why could she speak sometimes but not always? How did she know the uses of the Tarnhelm and Ring, and how did she know about Brünnhilde? Was she afraid of Siegfried, or drawn to him?) Ronnita Miller made a brief but arresting appearance as Erda, singing in a deeply rooted voice that rumbled like thunder. In the last part of the third act, Siegfried finally awakened Brünnhilde, who gave us the most glorious singing of the whole opera. Soaring high notes on “Heil dir” are a requirement for a good Brünnhilde, and Iréne Theorin did not disappoint. Where she astonished, though, was the honeyed, floating sound she spun for “Ewig war ich, ewig bin ich…” The aching beauty of her sudden, quiet sweetness caused gasps in the audience around me.

Rumor has it that conductor Donald Runnicles was under the weather on Friday night. It didn’t show in the orchestra’s playing. Tempi were blessedly fast. (Siegfried has a tendency to drag, but Runnicles paced it well.) Musical highlights included ominous drums near the end of the second act (as Siegfried pondered burning the bodies) and house-shaking blasts in the Act 3 prelude. Special mention goes to Laura Griffiths for comically sour notes on the English horn in Siegfried’s reed scene and to Kevin Rivard for perfect French horn solos.