Whatever its merits, the opera Dark Sisters, co-commissioned by Opera Company of Philadelphia and locally premiered Friday, has always had faces — magnetic ones that drew you into its rural, buttoned-up world of Church of Latter-day Saints sects that still practice polygamy. Even amid the mixed success of the opera's world premiere in November in New York City, the inner lives of its submissive wives were, if nothing else, revealed in eyes, hair, and chin lines that emerge from their near-identical prairie wear.

Now, as seen at the Kimmel Center's Perelman Theater, those faces are part of much more fully fledged beings. Though the opera's odd, parallel-universe Americana was easily viewed from a bemused distance before, you're now able to more fully enter a world view that occupies an extremely circumscribed sliver of Earth, but exults in a Mormon cosmos encompassing angels and planets that make Star Wars seem prosaic. It's now every bit the entrancing experience it was not at its premiere. In fact, Dark Sisters may be a significant addition to the chamber opera repertoire.

Changes have been incremental and subtle, but the most important shift is in the performances. The opera begins following a state raid on the remote LDS compound, with the wives singing the biblical-sounding names of the children who have been taken away from them. On Friday, the singers did so with a restraint that revealed the music's counterpoint, as well as the psychological place that each character occupies within it. The voices now articulate the characters as much as the faces.

What proceeded was a coalescence of theatrical elements necessary in an opera that can get lost in contemplative vagueness. Though deftly written, the Stephen Karam libretto portrays reactions to events more than the events themselves. Similarly, the Coplandesque expanse of the Nico Muhly score moves among set pieces, narrative passages, and occasional references to hymn tunes so fluidly that you mostly notice shifts of dramatic tension rather than which dramaturgical zone the music happens to be in. So it's not surprising the key catalyst for focusing the opera is Rebecca Taichman's stage direction, which homes in on the fine points of each character's physicality more than ever, making relationships as clear as those in a chess game. In this case, the better you see the opera, the better you hear it.

With her knitted brow and patrician looks, Eliza (sung by Caitlin Lynch) was established as the questioning wife who can't see why religious revelations should be limited to her husband/prophet. With her round face and kind demeanor, Almera (Jennifer Check) was devout and unquestioning, and lovingly unjudgmental to those around her. With her on-the-edge emotionalism, Ruth (Eve Gigliotti) was a portrait in post-traumatic stress, having lost her children to accident and illness. The ensemble work among them and the three other excellent female characters was of a caliber rarely enjoyed in opera.

The stronger Act I setup has a positive impact on Act II: At the premiere, an extended talk-show scene seemed jokey, with a faux-compassionate TV host prompting the women to plead for the return of their children. Now, the host is more restrained, and the women are more heartfelt, especially after their faces no longer appear on a TV studio monitor, which disappears to reveal a larger on-stage screen, where you truly have a chance to study their faces. The atmospheric video design by Leo Warner and Mark Grimmer once had to bolster the opera; now it's icing on the cake.

The Perelman Theater acoustics revealed more details in Muhly's orchestration than was apparent in New York. It's far better than it initially seemed. The only missteps are when Muhly illustrates a psychological state rather than portraying it — a cooler, less-visceral way to go. Eliza's Act I monologue has her contemplating her life with jagged, fragmented vocal lines that made sense in retrospect, but, in the moment, projected only confusion. (The rest of the monologue is glorious.) In Act II, when one of the wives contemplates suicide, the wandering vocal lines suggest an unhinged mental state, but they lack pathos.

By the end, I still want more opera. This two-act piece could easily have a third to encompass the scope of a story that, in its oddball way, reflects so many aspects of American life. As it stands, the opera tells only half the story. Repression of women is one thing. But how do the men get them to submit? And who are these guys?

Contact David Patrick Stearns at dstearns@phillynews.com.

Dark Sisters Music by Nico Muhly, libretto by Stephen Karam, direction by Rebecca Taichman. With Caitlin Lynch, Eve Gigliotti, Jennifer Check, Margaret Lattimore, Jennifer Zetlan, Kevin Burdette, and Kristina Bachrach. Opera Company of Philadelphia Orchestra conducted by Neal Goren. At the Kimmel Center's Perelman Theater Wednesday, Friday, and Sunday. Information: 215-893-1999 or www.operaphila.org.