Heartless is a Sam Shepard play. I use the phrase, cautiously, to curb potential confusion. Over the last few decades, New York has seen a fair number of plays by Sam Shepard that are not what I would call Sam Shepard plays: They offer his language, his sensibility, the sort of characters and ambiance on which he has often drawn, but they offer these elements in a flat, straight-dealing fashion. Easy to consume, they leave a longtime admirer hungry for the density of his peculiar method—"peculiar" in the sense of "distinctive" as well as that of "odd" or "eccentric." Anyone wanting to mimic his manner could write what looks like a play by Sam Shepard, but nobody else could possibly write a Sam Shepard play. Heartless, I happily reiterate, is a Sam Shepard play.

My happiness comes, in part, from its having been such a long time between drinks. I feel guilty even writing this sentence, but the last work to strike me as a Sam Shepard play was Fool for Love, nearly three decades ago. I don't say that Shepard has done nothing in the interim. As movie star, director, rock musician, horse farmer, writer of prose and of screenplays, and quasi-mythical cowboy icon, he has had plenty to keep his time occupied. My only complaint, reviewing works like The Late Henry Moss, Simpatico, and God of Hell, was that his mind did not seem to have been wholly in the theater when they were written. A Lie of the Mind (1985), which has had two major Off-Broadway productions, seemed to me less a Sam Shepard play than a Sam Shepard compendium, ingesting all the themes of his prior plays into one big clearance sale, as a way of saying goodbye to the theater. The works that followed it, though not without their individual charms, felt like postcards from elsewhere.

Heartless is quite a different matter. It could only take place in the theater; a film or television production of it would be nonsense except as a record of its theatrical performance. While it declines, firmly but politely, to make certain kinds of literal sense, and has already started to make those who pursue logical explanations extremely unhappy, it follows a single, straightforward action through a beginning, middle, and end. The action just happens not to be based in the simple reality we think we perceive on the surface. Shepard has never particularly cared for that surface reality. He is a modernist—these days with a lot of postmodern sauce to his meal—who has found inspiration in painting and poetry as often as in the theater. The figures in his plays make sense onstage together, but in exactly the same way that Botticelli's allegorical figure of La Primavera makes sense on the back of the bowler-hatted man in the Magritte painting. Like Magritte, Shepard twists reality, he disrupts its surface, he delights in presenting contradictory data. His reality is not to be absorbed glibly like the TV kind.

The superficial world that video cameras record supplies a sort of running gag in Heartless. The hero, Roscoe (Gary Cole), a 65-year-old scholar, has abruptly left his wife and kids to run off with half-his-age Sally (Julianne Nicholson), whom he met while she was interviewing him for a talk show. Roscoe, a Cervantes scholar, apparently has a quixotic enough spirit to fall in with Sally's suggestion that they collaborate on a documentary of his life, so he ditches his old Kentucky home to hole up with her high in the Hollywood hills, where her wheelchair-bound mother, Mable (Lois Smith), lives, crankily, attended by Sally's glum older sister, Lucy (Jenny Bacon), and an eerily mute nurse, Elizabeth (Betty Gilpin). As one can guess early on, Roscoe, having arrived with one woman, leaves with another: Love, like documentary realism, proves unreliable. And what we're all looking for in this world, as Mable sourly remarks, is someone whose "unconditional loyalty" we can always rely on.

But as she also remarks, another person's "whole story" "is something that eludes us, isn't it?" It certainly is when Shepard's telling it. Sally turns out to have a traumatic backstory that she hasn't shared with Roscoe, despite its having left its mark on her body. Elizabeth has a backstory, too, one that pulls the play into the metaphysical arena. (Hint: Shepard employs, though less literally, a tricky device also used in the recent Broadway musical Next to Normal.) And Mable, whose feisty, iconoclastic talk constantly belies her inert body, seemingly has a whole layer cake of such stories: The hideous accident that left her crippled, which occurred after her husband walked out on her (a little echo of Roscoe's situation here), apparently took place in 1955. And yet—the man who walked out on her was Lucy's father, Lucy and Sally are not so far apart in age, and Sally says she was born in 1982.

Maybe Mable is a horrific picture of everybody's mother (she says that Whitmore, her husband, "was everybody's father"). Or maybe Shepard, like a cubist painter, has superimposed several editions of Mable upon one another. You never know with Shepard. In many ways the play suggests a rethinking, the same only staggeringly different, of his 1971 collaboration with Patti Smith, Cowboy Mouth, which graphs a similar incident in the life of a much younger hero who, like Roscoe, has many points in common with his author. Roscoe, like Shepard, is in his late sixties, is based in Kentucky, and had an East Village "junkie period" in his late teens. His specialties, besides Cervantes, are Borges and the Argentine novelist César Aira; the names supply very clear signals to what's up in the writing.

Funniest of all is Shepard's treatment of Roscoe's dog, who carries the Sherlock Holmesian gimmick of "the dog did nothing in the nighttime" to hilariously non-realistic extremes—until, of course, it gets real. The wonder and charm of Heartless don't come from its trickery, but from the very real passion behind it and poetry within it. In Daniel Aukin's lucid, somewhat dry production, the poetic feeling is vested most fully in Smith, who deploys it with fierce, snappish authority, and in Nicholson's truly heart-rending shifts from sharp-edged to vulnerable. And for unspoken poetry, Tyler Micoleau's subtly nuanced lights take the prize.