There’s one in every state: a middle town. A small ’burb situated directly between larger cities; a midpoint between two greater actions whose nature is an extension of its geography, where average is the norm and complacency is accepted, if not striven for.

Identical houses line up along quiet streets in a middle town. Neighbors lend helping hands in a middle town. Parents let kids play outdoors into dusk without fear in a middle town. One can settle, relax and not worry about anything at all in a middle town. That’s how it looks on the surface, at least.

Behind every cheery greeting, sunshine smile, manicured lawn and white picket fence lies humanity. Projected perfections cover all-too-normal realities: dysfunctions, hidden truths, dark secrets. The sun may shine bright in middle towns across America, but reality lies in the shadows.

Middletown, the new play currently in production at Steppenwolf’s Downstairs Theatre, digs into the big problems confronting small town America.

Written by Will Eno and directed by Les Waters, it’s an ensemble affair rotating around the eponymous town’s denizens, but the focus falls on Mary, who’s just moved to Middletown with her mostly absent husband. They hope to settle down, raise a family and live the quiet American dream. Her husband’s absence — he travels for work — puts a crimp in the plans, however. Lonely Mary finds a friend in her older neighbor, the equally lonely John, a handyman by trade and eternal searcher of knowledge. They find comfort in conversation, but an ambiguity of intention seethes through — one with tragic potential.

Brenda Barrie, last seen on the Steppenwolf stage as the wonderful lead understudy in Sex with Strangers, and Pulitzer Prize-winning playwright and actor Tracy Letts star as Mary and John, respectively. Barrie was a revelation in Sex, but her turn in Middletown is surprisingly stiff and quiet. This could be due to the magnitude of Letts’ performance, however. His John owns the stage, but never overpowers it. It’s a very real performance, full of warmth, humor, sadness and deep pathos.

Mary and John’s back-and-forth fuels the play, but the characters in their orbit provide its life.

Cops, librarians, doctors, landscapers, janitors, tour guides, and even an astronaut hovering in space float in and out, talking amongst themselves (and at times the audience) about their lives, loves, hopes and fears. An existential edge marks these interactions and reveals their immediate universality in the process. It doesn’t matter where you live, the same troubles haunt us all — addiction, loneliness, depression, infertility, etc. The play brilliantly merges into extreme meta territory to further drive home this point with a pre-intermission interlude featuring actors on stage portraying patrons in the audience reacting to the play during intermission.

Middletown’s supporting players are all ace, but Michael Patrick Thornton rivals Letts for the standout spot. The wheelchair-bound actor, who can be seen on ABC’s “Private Practice,” plays the local mechanic who shifts around town when and medicates himself when he’s off the clock on whatever drugs are available. Through dry observations, hilarious asides and self-deprecating quips, he serves as the town’s soul, truth-detector and ultimately, its heart. His loud, ritualistic howl made at the end of the play — performed while facing the audience in full stereotypical Native American garb — chills to the bone. It’s a cry for the living and dying; a cry for the loved and the alone; a cry for everyone in every town and all points in between.