Before the music in the Metropolitan Opera’s new Parsifal starts, a black but reflective curtain drapes the front of the stage. It is dim enough not quite to show the audience, but it picks out the chandeliers. As Daniele Gatti coaxes the orchestra through the opening lines of the score the tableau becomes translucent, first seeming to mirror the front rows of the stalls, but slowly revealing the chorus, sitting in rows. Parsifal stands, in the centre, chosen. The men slowly remove their workaday suits, socks, and shoes, while the women turn. Director François Girard’s central conceit is clear: the Grail community is us.

What follows is another in a long line of Wagner productions set in a post-apocalyptic world. Michael Levine’s set is desolate, burned, and gravelly, with Peter Flaherty’s mesmerising videos projecting clouds that glow red and roil black, that darken, thunder, and eventually part. A stream cuts the ground, soon to be realised as Amfortas’ wound: the water turns to blood as the knight-leader is dragged on stage. Parsifal peers into the blood at the end of Act I, leading to a second act which takes place at the ravine-wound’s base. Act III returns to the Act I set, with the addition only of rough-dug graves.

In Girard’s telling, nature has been desecrated, just like Amfortas’ skin and the Grail’s community have been rent by lust and sin. With the male chorus – separated until the final bars from the women by the stage’s cleft – in shirts and suits throughout, one wonders if this is a post-climate change horror show, with the knights as guilty, faceless bureaucrats seeking a charismatic leader. Regardless, the theme of nature is picked up throughout, especially in vivid, abstruse projections in the transformation musics, with views of a planet, whole but dead, and shards of refracted sun breaking through. The clouds that dominate the background break only with Parsifal’s redemption.

The centrality of nature to this production is set alongside a focus on blood, and, relatedly, sex. Thousands of gallons of blood coat the floor of the frankly vaginal second-act set: Amfortas’ sin and Parsifal’s mother issues come together here. Klingsor’s Flower Maidens terrify in Carolyn Choa’s ritualised, deliberate choreography, mechanised and objectified as in previous knights’ dreams. Parsifal’s compassion – Mitleid – for Amfortas’ pain brings on yet more blood, now invested with life-giving, sacral power, just as in the redemptive Grail itself.

The steady, minimal staging of this Parsifal grows with almost unbearably powerful images. Take Parsifal climbing the back of the stage, silhouetted against a pillar of light, slowing seeking Amfortas and Kundry in Act III’s gloom. Or his pained walk across the stage divide to redeem Kundry, a simple but shattering move. In this Parsifal ritual deliberateness compels the audience’s collective sympathy with the stage action. From the start, we are all guilty, and all to be redeemed.

But Girard never quite does enough to elucidate what he really has in mind with this ritually sad, beautiful production. The separation of male and female as the course of all woe is a fascinating idea, but it is never clear what the women have done in the past, nor what role they are to play in the future. Clearly Girard wants to complicate Wagner’s gender roles, to the extent that Kundry carries the Grail to the knights so that Parsifal can redeem them. But is she redeemed only to serve? Does she redeem the women, or does Parsifal? And why, how? Or is there a different kind of Mitleid at work, that of mutual, true love? That seems to be the impression Girard aims for by the sensuous female flesh projected to represent the Grail's temple: flesh tempts, but, through Christ, it also sanctifies and regenerates.

In this production, Girard, like Wagner himself, leaves questions unanswered – unlike the composer, he leaves too many.

Redemption in Parsifal is seen on stage, but it is felt and ultimately believed in the ears. Intriguing as Girard’s production is, this Parsifal is most astonishing for Daniele Gatti’s conducting. It is slow, but so filled with detailing and clarity that it could easily last longer. Dramatic action took place first and foremost in the orchestra, Gatti expertly controlling its sound, keeping an impossible fragility in the outer acts and finding screwed-up modernist horrors in the second. Such was Gatti’s control over colour that one thought Wagner had beaten Schoenberg to his Klangfarbenmelodie punch. But it was his delivery of architecture, with a liturgical power that built inexorably and geometrically, that was most impressive, and most important. He did it from memory, too.

Few better casts could be imagined than the one the Met has assembled here. Jonas Kaufmann is the rare Wagnerian hero you can believe in. He traced Parsifal’s progression from fool to Erlöser with subtle movements and an aging, darkening tone. His two main monologues ideally married words and line with scarcely conceivable power and dramatic nuance, all the while deploying his formidable acting skills. His final word, “Schrein”, sticks in the memory for its half-tone delivery, matched seamlessly to the tenuous thread in Gatti’s strings. René Pape’s is a Gurnemanz of tortured nobility and textual accuracy, with enough gravitas to act as the production’s moral centre. Peter Mattei conjured a wretched Amfortas, forcing our empathy, straining with physical difficulty but delivering a long line to match that from the pit. Yevgeny Nikitin’s venomous, predatory Klingsor was rather caricatured, but then Wagner’s sorcerer is. Katarina Dalayman was perhaps the weakest link as Kundry, with a particularly squally top to her voice, but she invested her role with great emotional force. Minor characters were ably done, and the chorus was particularly fine.