In the 1960s, Sam Shepard was making his name in Greenwich Village's experimental scene with fractured, restless one-acts. In a 1965 Village Voice review of one of these works, playwright Edward Albee wrote that the hallmark of Shepard's work was "unencumbered spontaneity—the impression Shepard gives of inventing drama as a form each time he writes a play." (Unfortunately for Shepard, that particular play gave "the impression of being a mess.")

Buried Child, the 1978 work that catapulted Shepard to fame and earned him a Pulitzer, definitely did not give such an impression: The play had a clear setting and a mostly lucid (if grim) storyline of family dysfunction, incest, adultery and infanticide. Yet it wasn't a clean shift to realism either. Buried Child has a surrealistic, rootless quality, as if its characters exist on another metaphysical plane. This makes it a difficult work to stage, and as much as this Profile production plays up the drama's strange volatility, the cast is uneven.

After opening its Shepard season with the little-produced Eyes for Consuela (Profile devotes an entire season to a single playwright), Buried Child is a smart choice by director Adriana Baer. The play is both a sweeping family drama and a claustrophobic study of what unfolds over the course of 24 hours in a living room in rural Illinois. On his drive across the country with his girlfriend Shelly, prodigal son Vince stops by to visit family he hasn't seen in six years. But everything is wrong. His surly grandfather Dodge claims not to recognize him, and his father behaves as if lobotomized. Bradley, his one-legged bully of an uncle, isn't particularly welcoming either: In an indelible moment, Bradley demands Shelly open her mouth so he can stick his fingers clear to her uvula. Over the course of the next day, the family's secrets—namely the one that lends the play its title—are cruelly aired.

Nothing, though, is so straightforward in Shepard's world, so the play is shot through with macabre humor, lyrical imagery and magical realism. What, for example, explains the sudden appearance of corn in the family's long-fallow field? The set is wonderful: a mustard-yellow couch hulks in the center of the stage, looking ready to pick a fight with anyone who dares try to move it, and the house is represented by skeletal beams and windows, with a backdrop of a jagged-edged sky.

Where this production starts to lose hold is in its performances. Shepard's characters are shape-shifters, matter-of-fact one moment and melodramatic the next, a challenge some cast members handle ably. As Dodge, Tobias Andersen is marvelous. All hacking cough and pinched eyes, he shimmies his jaw from side to side and stashes his whiskey between the couch cushions—and when that bottle disappears, his frenzied search for it is uproarious and heartbreaking. Humor and tragedy also intersect in Dodge's interactions with Shelly, played by Foss Curtis with just the right stew of bewilderment, humanity and moxie. Their rapport has a sharp bite, but it's also suffused with a sense of longing. And as Dodge's adulterous wife, Halie, Jane Fellows swings weirdly—but effectively—from venomous to falsely cheerful.

But as Vince, the stiff Ty Hewitt lacks the same grasp on his role. With his unvaried vocal register and purposeless hand flailing, he moves from odd petulance in the first act to unfocused rage in the second. Vince should be the stone that knocks the family's wheel off course, but when Hewitt is onstage the action threatens to unravel. Buried Child should feel off-kilter—just not this unsteady.

SEE IT: Buried Child is at Artists Repertory Theatre, 1515 SW Morrison St., 242-0080, 7:30 pm Thursdays-Saturdays (and Wednesday, June 11) and 2 pm Sundays through June 15. $30.