How extra tortuous to find oneself out in the desert (in John Ford’s Monument Valley, no less!) with Wim Wenders’ personality crisis drama “Don’t Come Knocking.” Starring Sam Shepard (who also wrote it) the film offers an interesting premise about Howard Spence, a noted star of Western movies (as if such a thing existed these days) who feels washed up enough to high tail it out of his latest feature on the nearest gelding and ride back into his hometown to hide out. Along with batches of cookies and scoldings about rudeness, his mom (Eva Marie Saint) saddles him with the news that he has a grown son, whom he fathered somewhere in Montana on a shoot.

Howard has lived a debaucherous life, even for a Hollywood playboy. The title “Don’t Come Knocking” is both a play off the old phrase that begins “If this truck’s a rocking …” and a summation of the way Howard’s former acquaintances now feel about him. But Shepard and Wenders are the ones who seem truly out in the sage brush. Examples of a movie succumbing to its own inertia: Scenes of driving down a highway are some of the most interesting; time-lapse photography is repeatedly brought into play; Shepard also repeatedly uses dialogue to explain the plot and back story, often to ludicrous effect.

Wenders doesn’t come off much better. During one scene, after Howard and his new-found son (Gabriel Mann) get in an argument, the director circles his star so many times the less credulous would be inclined to start thinking they were in the midst of parody. Sad to say, this varmint is for real. ** S