"The curtain of my eyelids is raised ... Old is this castle, Old is the tale enclosed by its walls. Observe carefully."

What is this? Even those familiar with Bartok's one-act opera Bluebeard's Castle don't often hear the ominous but often-cut spoken prologue employed Thursday at the Philadelphia Orchestra performance at Verizon Hall.

Intoned in heavily amplified Hungarian by the evening's bass soloist, John Relyea, the prologue establishes that this 1911 portrayal of Bluebeard is not some bloody horror show, but a French Symbolist parable -- as the legendary lady killer attempts to "go straight" with his final wife, Judith, but fails as she demands to see what's behind every door in his castle.

The gradual psychological submission should feel like what Fifty Shades of Grey pretends to be. But this enterprising program with the opera (in concert form), paired with excerpts from Tchaikovsky's Swan Lake, didn't entirely come together, which meant Bartok was more episodic than entrancing. Yet the meticulously fashioned orchestration, more like Strauss than mature Bartok, makes the opera, if nothing else, a dazzling showpiece, especially with music director Yannick Nézet-Séguin on hand.

The sinewy opening bass lines felt particularly reptilian. And as different floods of sound issued forth when each door opened, the vast vista of Bluebeard's realm had the orchestra in full cry (as only it can do) with the Fred J. Cooper Memorial Organ adding an inner electric current.

The opera's more muted portrayal of Bluebeard's lake of tears touched on the infinite sorrow that created it. Often, Nézet-Séguin uncovered odd little quasi-medieval musical references, adding to the sense that time melts together in this world. The piece is a bottomless pit of orchestral possibilities.

But it's also an opera whose narrative depends on its two characters. Mezzo-soprano Michelle DeYoung and bass Relyea were positioned on each side of Nézet-Séguin, which felt right in an opera when the two characters often seemed to be calling to each other from a distance.

The orchestration is likely to cover the singers no matter where they're positioned, but DeYoung was fully audible, at least from my first-tier seat, only in moments with the thinnest accompaniment. Her character's emotional journey seemed to be portrayed with only one, all-purpose vocal color.

In purely vocal terms, Relyea delivered one of the strongest performances, his language projection having an authority that greatly suited his character. But when Bluebeard starts rhapsodizing about his past wives (who aren't murdered but who become Stepford Wives), his vocal manner doesn't follow the orchestra into this new emotional realm.

And Swan Lake? Though the excerpts touched on the story's dark side, most music chosen for this concert -- which is headed Tuesday for Carnegie Hall -- were tuneful sections written for the sake of pure dance. Nézet-Séguin allowed himself moments of particular extravagance. After all, it's ballet.

The program is to be repeated at 8 p.m. Saturday at the Kimmel Center. Information: 215-893-1999 or www.philorch.org.