It’s 1808, and on a farm just outside Philadelphia, the frontier consumes the thoughts of Susanna Cox (Anne Veal), an indentured servant.

Signature commissioned playwright Bathsheba Doran to tell the story of what happens when the open promise of America clashes with certain ugly truths about Americans. The real Susanna Cox was put to death by the state of Pennsylvania in 1809 for the crime of infanticide. Her tale is uniquely American, involving all our national obsessions: sexuality, class, gender roles, the search for national identity, and, most of all, the insidious, hypocritical piety coded into our cultural DNA ever since the first boatload of buckle-shoed Jesus-freaks landed at Plymouth.

That’s a lot of big ideas, which is pretty much the problem. Doran is particularly deft at constructing dialogue filled with small, characterizing moments to elucidate her themes. But because those moments never quite cohere, the script fails to step fully out of the world of big ideas, and a lack of visceral, empathetic humanness persists.

At Signature, it’s left to the director and the performers to enrich the thematically lush but dramatically thin proceedings with emotional nuance. And that, with very little fuss, is exactly what they proceed to do.

Joe Calarco’s sensitive direction and strong, finely shaded performances from the cast serve to round out most of the script’s unfinished edges. Everything in the production, from the simple, minimalist intimacy of James Kronzer’s set to the shadows that slant across Signature’s small Ark stage, is marked by an admirable subtlety and restraint.

Case in point: There’s a scene about midway through in which Susanna takes a series of brutal steps to get rid of her pregnancy while, across the stage, a chaplain (Stephen Patrick Martin) delivers a pious sermon to his flock on the cruelty of man. As written, the juxtaposition is so literal it seems pushy, and Calarco knows it. So he and the actor have created a chaplain who is less fire-and-brimstone and more peaches-and-cream: gentle, soft-spoken, and humane. The choice transforms what would otherwise be a screed into something surprisingly compassionate and revelatory.

Similarly, Elizabeth (Vanessa Lock), the female head of the household that employs Susanna, is saddled with many lines that could—and, in any other production, likely would—paint the woman as a prim, humorless caricature. But Lock’s line readings are so nuanced and utterly real that she defies the script’s attempts to flatten her. In fact, she earns every laugh she gets, often with little more than a shift in the tone of her voice. In her skilled hands, a not particularly yuk-worthy line like “And from that day on, nothing at all worked out as I thought it would” absolutely kills.

It’s not until the play’s closing moments that you realize your emotional involvement is not where it should be: The ballad sung so mournfully by the cast should be more haunting, Susanna’s last moments more wrenching. From the earliest scenes, Doran’s contemplative script and Calarco’s thoughtful, undemonstrative direction have engaged the mind but not the gut. Nest ends up a very pretty creation that’s unnervingly cool to the touch.