Two singers perform ‘As One’

Baritone Scott Ballantine as Hannah Before and mezzo-soprano Rebecca Krouner as Hannah After in “As One.” Dan Busler

CAMBRIDGE — Not many operas come with content warnings for violence. Perhaps it’s expected that someone will be hurt or killed at some point. But at Boston Opera Collaborative’s affecting, compelling opening night of Laura Kaminsky’s chamber opera, “As One,” at Longy School of Music of Bard College’s Pickman Hall on Thursday, a content warning was given both in the program and from the stage.

Hannah, the opera’s sole character, is a transgender woman. The single scene of physical violence in “As One” does not end in death, but it hits close to the headlines. And by that scene, we have come to care deeply about Hannah and her journey.

It takes two singers to make Hannah, one each to represent the periods of life when she lived as a man and as a woman. Baritone Scott Ballantine’s earnest Hannah Before was vocally precise, but his acting was somewhat two-dimensional. Mezzo-soprano Rebecca Krouner’s Hannah After unleashed a torrent of expression, exulting in wordless curlicues of sound in joyful moments, and snarling and weeping during the violent scene. Both singers were on stage at all times, and though the balance of the singing shifted from Ballantine to Krouner over the course of the opera, each was always an indispensable part in the complex drama. Hannah’s “after” self exists from the start, and her “before” self is not erased when she transitions.

“As One” unfolds in a series of vignettes, starting with Hannah’s being raised as a boy somewhere where the library still has a card catalog and she’s never heard the word transgender. It follows her through her transition, the “second puberty” of hormone-replacement therapy, and a heart-wrenching scene where she writes a letter making her excuses for not coming home for Christmas. Finally, after being attacked by an unseen stranger in a tableau set against a litany of names of the lost, including that of recently murdered Massachusetts trans activist Christa Leigh Steele-Knudslien, Hannah seeks peace in a solo retreat to Norway.

The plot was loosely based on the life of co-writer Kimberly Reed, a transgender filmmaker who also provided video projections to the production. The ever-prolific Mark Campbell collaborated with her. Kaminsky’s string quartet score is woven from personable post-minimalism with some taut, atmospheric segments.

If there’s one weakness in Hannah’s story, it’s that in different hands her final resolution to “be happy” could feel too tidy. However, Krouner and Ballantine’s last scene didn’t so much say “end” as “beginning of an unwritten next chapter.” Friday and Sunday’s performances will feature Andrew Miller and Jaime Korkos as Hannah.

Since its premiere a few years ago, the opera has been performed many times. The melodies of “As One” may not have sticking power, but the story definitely does; and the opera is feasible for companies of all sizes and budgets, and accessible enough to audiences for it to sound for years to come.

BOSTON OPERA COLLABORATIVE

At Longy School of Music of Bard College, 27 Garden St., Cambridge, Thursday. Repeats Friday through Sunday.