Any work of art about polygamy runs the risk of turning into propaganda. “Dark Sisters,” the 2011 chamber opera with libretto by Stephen Karam and music by Nico Muhly, is as locked into its assumptions as the five wives of its Prophet are into plural marriage. In the Boston University Fall Fringe Festival’s well-sung and well-acted production in the Lane-Comley Studio 210 black box, the only thing to break free is Eliza, the wife who shakes the dust from her shoes and leaves.
The inspiration for “Dark Sisters” — which runs two hours, with a 10-minute intermission — is not the mainstream Church of Jesus Christ of Latter-Day Saints, but the splinter Fundamentalist Church of Jesus Christ of Latter Day Saints, which peeled away in the early 20th century when the parent church renounced polygamy. At the outset of the opera, officials raid the FLDS ranch and take the children into custody after receiving reports of child abuse and underage marriage. The wives lament the removal of their offspring. Eliza, however, is even more upset to learn that the Prophet has promised their 15-year-old daughter to a 56-year-old church elder. In the second act, the wives appear on a TV talk show to plead their case, but Eliza goes off script. She and Ruth then exit, each in her own way.
There’s material for dramatic conflict here, but Karam’s black-and-white libretto doesn’t locate it. This Prophet demands total obedience; his wives call him “Father,” and they seem like zombies when reciting their “We just care about the children” mantra. Zina, Presendia, and Almera are virtually indistinguishable. Ruth is traumatized by the loss of a son to cancer, a death the Prophet has attributed to her lack of purity. Only Eliza stands up to her husband, asking why she shouldn’t have a Revelation of her own.
David Gately’s staging for the Fringe Festival is appropriately minimal, the set consisting mostly, and not so subtly, of beds slid out into the playing space from the audience. Muhly’s spare score, reduced from the original 13 instruments to Noriko Yasuda’s piano and Greg Simonds’s percussion, doesn’t convey much more than the same jittery hysteria for each wife. Toward the end, he introduces “Abide With Me”; I wish he had set that hymn-like sensibility against the nervousness from the start.
In Friday’s opening-night cast (there are two), Kelly Hollis was a wistful, open-eyed Eliza, and Stephanie Zuluaga gave a chilling rendition of Ruth’s “I’m ready to come home” aria. Jorgeandres Camargo made for a callow Prophet and an equally ingenuous talk-show host, but who could be convincing with lines like “If you’re all married to the same man, under US law, that is illegal”? We know it’s illegal. “Dark Sisters” needs to tell us how it might be all right.