When I made plans to see Nautilus Music-Theater’s adaptation of “Joan of Arc” — its first fully staged production in the company’s small, Lowertown loft studio space — I have to admit, I was a bit dubious. Thinking of the medieval French peasant girl-turned-soldier of God, her famously transcendent visions and fiery end — the high drama of Joan’s embattled against-the-odds courage and her ultimate betrayal means there’s loads of potential for a stage adaptation. But I could also think of so many ways for a musical theater rendition of the tale to jump the rails.

I shouldn’t have doubted. The libretto, by Laura Harrington, is starkly poetic, its plainspoken narrative and lyrical simplicity perfectly suited to the humble but charismatic visionary at the story’s center. Mel Marvin’s musical score is also pitch perfect for the subject at hand, with songs marked by simple but soulful melodic lines and harmonic structures inspired by traditional European sacred music.

And then there’s “Joan,” played with artistry and unerring assurance by the hugely talented Jennifer Baldwin Peden. Her compelling narration of the plot, resonant affinity for the character and angelic soprano are equally and utterly riveting.

The production strips Joan of Arc’s story to its narrative and spiritual bones, taking place after our unlikely heroine has successfully led the French armies against the English, but after her capture and subsequent betrayal by her one-time patron. We meet Joan in her prison cell, condemned as a heretic and blasphemer by the Church, undergoing an unjust trial.

The stage design, her jail cell, is appropriately Spartan: a length of catwalk, with barred windows at each end; the narrow runway of the stage is flanked by seats for the audience, 20 or so on each side. When Joan is addressed, it is by unseen voices heard through one of the two windows: through the barred opening on one side, unseen accusers offer abuse and a litany of the charges against her; through the window on the other side of the stage, we hear Joan’s divine voices, a small chorus of angels and instrumentation who lend her support throughout her ordeal. The costume design is straightforward, too: she is barefoot, wearing drab camouflage pants with a canvas flak jacket and dun-colored T-shirt.

As she’s rarely more than an arm’s length from any of us in the audience in this intimate performance, Baldwin Peden’s poise is all the more remarkable. In fact, her proximity and conviction of character serve to deepen the emotional investment we have in Joan’s plight. The night I went, the small audience was spellbound, at the edge of our seats, for the duration of the play’s 70-minute run time.

Simply put — Nautilus Music-Theater’s “Joan of Arc” is the most moving performance I’ve seen this year. I believe tickets may already be sold out for the rest of the show’s run, so if you’ve landed one, count yourself lucky. You’d be hard pressed to find a more rewarding night of theater than this.

“Joan of Arc” by Nautilus Music-Theater runs through Nov. 6 in the Nautilus Studio inside the Northwestern Building, 308 Prince St., #250, St. Paul, Minn. Ticket information is available online: http://www.brownpapertickets.com/event/205875.