Prague’s National Theater got an adventurous new opera season off to a rip-roaring start with Pád Arkuna (The Fall of Arkun), a Wagnerian epic by Zdeněk Fibich that has not been produced in the Czech lands for more than 80 years. Resurrected by American conductor John Fiore and Czech director Jiří Heřman, the piece offers all the elements of great opera – a gripping story, enchanting music, the grand sweep of history – and a refreshing encounter with a nearly-forgotten composer.

Fibich, born in Eastern Bohemia in 1850 but raised and schooled mostly abroad, was a Romantic whose work never caught the Czech imagination the way his nationalist contemporaries Smetana and Dvořák did. He is known now mostly for the piano piece “Poem” (from the collection “Moods, Impressions and Souvenirs”) and the opera Šárka. He finished Arkuna, his seventh opera, in 1899, and after contracting pneumonia died before it premiered at the National Theater in November 1900.

Arkuna is ambitious in every way, starting with its structure: a one-act prologue titled Helga, set in 12th century Denmark, followed by the three-act opera Dargun, set 20 years later on the island of Rügen in northern Germany. In the former, the title character is engaged to the Christian warrior Absalon, but becomes pregnant by the pagan chieftain Dargun. A confrontation between the two men is inconclusive, but Absalon vows a future resolution. When they meet again in the second opera, Absalon is a priest leading a crusade to destroy Dargun’s pagan cult at the Temple of Arkun. Helga is long departed, but her daughter Margit makes a terrible discovery amid the bloody treachery of Dargun’s court, where the scheming princess Radana is willing to murder her own husband to get what she wants.

If the plot leans heavily on Shakespeare and European religious history, the music virtually stands up and salutes Wagner. Written as a continuous music drama packed with powerful leitmotifs, the score is often more expressive than what the characters are saying and doing onstage, roiling with emotional undercurrents and punctuating dramatic declarations and moments of realization with sonorous blasts of brass and percussion. Fibich has his own ideas – there are lovely melodies throughout, and the erotic charge in Radana’s vocals presages the modern era. But from the moment Helga and Dargun are standing at opposite ends of the stage trading extended lines of emotional distress, it’s clear we are in Wagner territory.

Which made Fiore a perfect choice at the podium. A well-practiced Wagner hand – he started at the age of 14 as the rehearsal pianist for the Seattle Opera’s Ring productions – Fiore helmed an impressive Ring cycle in Prague in 2005, and cemented his relationship with the National Theater orchestra in subsequent productions of La fanciulla del West and Parsifal. He drew a rare passion out of the ensemble for Arkun, not to mention a striking show of stamina, with première performances pushing four hours on successive nights. The sound was rich and consistently colorful, by turns dramatic, tender and thunderous without ever losing a note of nuance.

Often, the music propelled the narrative better than the action (or lack thereof) onstage. After the Friday performance, Hungarian soprano Szilvia Rálik and Czech tenor Martin Šrejma received warm applause for their work as Radana and the good prince Jaroměr. But the biggest hand was reserved for Fiore and the orchestra.

Heřman unnecessarily complicated an already tangled and unfamiliar story with some unfortunate choices. He modernized the setting, with Dargun running a merchant marine instead of a pagan cult. This made for some stunning videos of passing cargo ships, but begged the question of why a priest was determined to bring down a shipping empire. Worse, he turned an historical epic into a domestic melodrama by keeping Helga at center stage – literally. Though she dies between the prologue and main opera, her character continued to wander the stage, first as an observant ghost, then an unseen hand steering events, and finally as the linchpin of the entire piece, holding hands with other characters in the climactic scene. This was more than confusing; it robbed Dargun of its focus on the protagonist and any sense of suspense or discovery.

Though he handles love scenes adroitly, Heřman’s action sequences were glaringly weak. A murder in the prologue was so clumsily done, it was unclear how and why the character was dying. Bad crowd management and wooden, slow-motion acting drained Dargun of much of its vitality, with most of the action in the final act inexplicably taking place behind a scrim.

For all that, Pád Arkuna offered a highly entertaining night of opera, not least because of the excitement of seeing a new work. Many operas come and go because they don’t merit more than a single listen. This one is a victim of its own ambition, a challenging production in a language that not many singers outside the Czech Republic can master. But as a bracing and intelligent synthesis and reflection of its time, it’s a revelation.