Many years ago, after struggling to make sense of a one-act in acting class, I confessed to my teacher that I didn’t have the slightest idea what the play was about. “Of course you don’t,” she replied. “The playwright’s just whacking off.”

That particular insight into Sam Shepard’s dramaturgy has kept me in good stead ever since—from The Tooth of Crime all the way to True West—and it’s as useful a principle as any for approaching the strange shambles that is Don’t Come Knocking, Shepard’s latest collaboration with Wim Wenders. The last time these two hermetic talents got together, you may recall, they produced 1984’s Paris, Texas, in which Harry Dean Stanton wanders in and out of arid and semiarid landscapes searching for himself and his lost family. That’s pretty much the same arc the current film follows, except that Shepard plays the wanderer: a fading Western movie star named Howard Spence who goes AWOL from a movie set in Utah.

Driven at first only by a vague itch to be gone, Howard soon learns that he has a grown son living in Butte, Mont. He resolves to see the boy for himself—not to mention the kid’s still-fetching mama (Jessica Lange). Too bad about that bond-company investigator (Tim Roth) trying to drag Howard back to the set of his interrupted movie. Too bad, too, that Howard’s old girlfriend still has major issues with him, and that the son in question (Gabriel Mann) wants no part of him. In fact, the only one who doesn’t mind being related to Howard is another long-lost child, Sky (Sarah Polley), a calmly formidable young woman who carries around her dead mother’s ashes in what looks to be a blue cookie jar.

All of which makes you wonder: Could any actor living in the 21st century still be a “Western movie star,” fading or not? Especially one working on a Marlboro-man oater that wouldn’t pass muster on TNT? It’s thoroughly absurd—though not as absurd as the notion that an actor so closely tracked by tabloids should wander through a large chunk of America virtually unrecognized. Or that a middle-aged Montana waitress/restaurant owner should look as fan-magazine-tastic as Lange (who could still spend a little less time with Faye Dunaway’s doctors).

By now it should be clear that verisimilitude is not the foremost concern of the Shepard–Wenders partnership. We are, by all appearances, in the land of fable. But a fable about what? The emptiness of fame? The resilience of family ties? Redemption? It’s anyone’s guess, and as its various threads unravel, the suspicion grows that even Shepard and Wenders aren’t on the same page, despite their shared fondness for dead-end streets, last-chance saloons, and all the other clichés of manly alienation Don’t Come Knocking may or may not be sending up.

Wenders has always been most intrigued by America’s wide, empty spaces, inner and outer, and he seems happiest in the movie’s silent interstices, when cinematographer Franz Lustig’s camera is turning toward whatever blur of loneliness is on the horizon. Shepard is drawn to performance, to people making scenes in every sense of the phrase. His characters constantly circle one another, using their native rhythms to dominate and metaphorically kill.

It’s no surprise that so many top-notch actors are drawn to Shepard’s work; it’s equally no surprise that his writing, at its worst, devolves into acting-class exercises—exercises of a fairly high caliber, to be sure, when performers like Lange and Roth and Mann are tearing into them. (Fairuza Balk, though, as Mann’s heroin-addled girlfriend, seems to be swallowing her scenes whole.) And Shepard himself has grown considerably as an actor since his haunted-hunk days of the early ’80s, when his performances consisted mainly of deepening the sexy furrow that creased his brow. The furrow is now part of a full complement of wrinkles, and Shepard’s palette has grown concomitantly fuller and softer. He’s even charming.

But no matter how well-played, a string of scenes without narrative justification is a string of scenes: honest labor for starving thespians. It’s ironic that the film’s finest performance comes from the actor who seems the least hungry for work. As Howard’s mother, Eva Marie Saint reminds us why she was once among Hollywood’s most sought-after leads. Rather than scrape herself against the nearest actor to see what sparks might fly, as Mann too often does, she portrays a woman who is resolutely on her own: someone who’s been alone for so long she’s forgotten how to resent it.

The character of Mrs. Spence disappears pretty early from Don’t Come Knocking, but more than once I found myself wanting to be back in her Elko, Nev., tract home, watching a ball game in the sad blue light of her television. Who knows? There might even be a story there—as opposed to the pageant of attitudes that Shepard and Wenders have given us.