IT ALL STARTED WHEN REBECCA GILMAN SPRAINED HER ANKLE. After a hiking mishap, the playwright ended up in the emergency room, sitting next to two young meth addicts. While one talked on the phone to what sounded like a babysitter, Gilman wondered to herself, “Would these two make good parents?”

A scene very similar to that one opens Luna Gale, Gilman’s play about a social worker in Cedar Rapids, Iowa, navigating the custody case of a young child of two teenage addicts. “I’ve been trying to write a play about a social worker for a while,” Gilman expresses. “I was really captivated by how much of their work comes down to their own personal judgment or intuition about things.”

Luna Gale marks Gilman’s seventh production at Chicago’s Goodman Theatre (where she is an artistic associate) and her fourth collaboration with Robert Falls, the Goodman’s artistic director, who is also directing the play. “It’s a cliché to say we finish each other’s sentences. I actually wouldn’t even presume to finish a sentence by Rebecca,” Falls says. “We know each other. We can say pretty much anything to each other without feeling like we’re offending the other.”

Steppenwolf Theatre Company originally commissioned the play, but when they passed, the Goodman picked it up for production. Falls says he was attracted to a story about the middle class, who are not often portrayed onstage. “Most plays sit between real extremes. They’re either about the affluent or the very, very poor,” Falls explains. “Luna Gale also sits in a unique midwestern setting. As a Chicagoan, I have a real interest in those stories.”