“Anna Bella Eema” bills itself as “a ghost story with three bodies for three voices” — that’s about as good a description as any. Obie Award-winning playwright Lisa D’Amour’s otherworldly script just doesn’t fit comfortably in the confines of a tidy subhead capsule description.

Here are the story’s outlines: A single mother, Irene, and her precocious 10-year-old daughter, Anna Bella, live in isolation, in the trailer park Irene herself was raised in, which will soon be razed to make way for the new highway coming through. Half-broken by the travails and hinted-at exploitations that marked her young life, the mother (a “postage stamp licker” by trade) has become both fearful and fey, largely abandoning reality and unable to cope with the family’s imminent uprooting. Instead, Irene and Anna Bella inhabit a self-made world of books and fables and “wild things” — where their roll-away bed in front of the TV becomes a sailing ship bound for storybook lands, where policemen are Frankensteins in disguise and little girls are menaced by vampires and werewolves in the deep of night. Anna Bella, made bereft by her mother’s increasing incapacity, creates a companion for herself, a golem girl/shadow self made from the mud outside their trailer, who accompanies her coming of age.

Theatre Unbound’s production of “Anna Bella Eema,” directed by Genevieve Bennett, is a scrappy, no-frills affair: the set amounts to three TV tables and folding chairs, alongside which are teetering stacks of books and repurposed white mail bins filled with household ephemera. From the chairs, the play’s three characters: 10-year-old Anna Bella (Jaime Kleiman); Irene (Maren Ward); and the “girl her girl made,” Anna Bella Eema (Katie Kaufman) — create the wildly imaginative tableaux spun in the minds of mother and daughter, using no more than spoken word and eerie songs, improvised percussion and sound effects and sheer force of will to do so.

Indeed, the script requires herculean efforts of the imagination, from both actors and audience; the challenging show would have foundered but for the utter conviction and commitment of the play’s talented cast. At more than a few moments, I felt the familiar stirrings of what I think of as “the avant-garde squirm” — the sort of feeling that, for me, accompanies, say, performances involving severed baby-doll parts and Ace bandages or nearly-nude dancers entwined in a gallery space, a little too close to me for comfort. But that squirm is an entirely appropriate response: the play is unabashedly and boldly bizarre, and necessarily so; its occasionally luminous moments of insight about the innate but often-discounted weirdness of being human are only obliquely accessible and can’t be gotten to with straight lines.

“Anna Bella Eema” defies neat classification — it’s a theatrical gesture, a prose poem-cum-fairy tale, a fractured operetta about the inchoate, wild contours of the distinctly feminine interior landscape. And it’s a worthwhile night of theater, too, if you’re feeling game for something out of the ordinary.

Theatre Unbound’s “Anna Bella Eema,” written by D’Amour and directed by Bennett, is on stage through Oct. 23 at the Lowry Lab Theater, 350 St. Peter St., St. Paul, Minn., 55102.