BEFORE SEEING Third Rail's new show, I told a friend what I knew of Gidion's Knot's premise: A parent and a teacher meet to discuss the problems a fifth-grade boy, Gidion, is having in school. "Was he bullied, or is he gay?" my friend immediately asked.

Good guesses both—and we'll leave them on the table—but more crucially, he's dead. Teacher Heather (Amy Newman) is understandably baffled when the mother of a recently deceased student chooses to keep an appointment for their parent/teacher conference, mere days after her son's death. But Corryn (Dana Green) wants answers: Who's to blame for Gidion's suicide? Why was he suspended from school on the day he died?

Corryn is a "medieval poetry professor," one of those jobs—like "playwright"—that seems to exist only in plays and movies about stressed-out white people. As played by Green, Corryn is reminiscent of Mary-Louise Parker in Weeds—her eyes are puffy but steady, and her guard never entirely drops. She seems to see herself as some sort of vengeful warrior poet, and her son the victim of a school system that suppresses individuality and creativity.

In contrast, Amy Newman's schoolteacher is conflict averse and timid—too timid, in fact, considering that the script informs us of her background working in advertising. (She doesn't scan as an adult professional in her second career.) Heather quietly but resolutely dodges Corryn's questions, even as Corryn grows ever pushier and more intense in her interrogation.

Playwright Johnna Adams' script is at its most intriguing when the two women are reconstructing the inner life of Gideon—reading his homework, excavating his desk for scraps of paper, trying to piece together the world of a boy both of them thought they knew. But because the conflict between Corryn and Heather doesn't feel evenly matched, the show lacks urgency on a moment-to-moment level. More than once, I felt as though I was trapped in school myself, watching the giant classroom clock tick down the minutes 'til the show's inevitably high-stakes conclusion.