Voices suddenly erupt and desks get turned over in "Gidion's Knot," the Johnna Adams play that opened over the weekend at the Pillsbury House Theatre in Minneapolis. But most of the dramatic action in the 75-minute one-act is not easily visible to viewers. It's what roils the souls of the play's tense characters. We see evidence of their internal storms in arrested breathing, in sentences that break off like ruptured bridges and, finally, in tears.

A topical two-hander about free speech, violence and the effects of bullying, Adams' play is a study in tragic tension. It is set in a fifth-grade classroom festooned with students' papers and projects (Joe Stanley created the realistic set that is lit by Michael Wangen; Clare Brauch designed the contemporary costumes).

The play's gravity is almost subverted by an opening that seems more fitting of a lighter play. It is the end of the school day as second-year teacher Heather Clark (Laura Esping) sits at her desk catching up on some work. There's a knock at the door. She sends the visitor to the office. A few moments pass, then there's second knock. The visitor has returned and again the teacher sends her away. Finally, there's a third knock. The teacher lets the person in. The visitor is Corryn Fell (Aditi Brennan Kapil), mother of a fifth-grader in the class.

She has come for a conference that the teacher had taken off her calendar. But Corryn, who we later learn is a professor and single mother, has kept the appointment because she wants to talk about her son.

"Knot" stretches credulity in at least one way. It takes place in the spring and yet the teacher and parent have never met. Still, director Noel Raymond's production is a solid one. She builds the action gradually in flawless blocking and in the gradual ratcheting up of the actors' lines.

Actors Kapil and Esping deliver performances that suggest two ill-fitting dance partners wholly reliant on each other. In most moments, Kapil leads (with words), dragging Esping, who clearly would rather not be there, along. But the momentum, and the power dynamics, also switches.

By the end of the evening, the two actors achieve a noble thing onstage. Their separate actions meld into one, with performances that support each other. But instead of building towering foundations, they show us their wounded characters, leaning into each other like broken pillars.

Rohan Preston • 612-673-4390