Show wears its heart on its sleeve

When Billy Ray Cyrus broke into the national consciousness more than a decade ago with a catchy crossover ditty titled “Achy Breaky Heart,” few predicted a long shelf life for his talents. Most pop-culture pundits figured he’d go the way of other one-hit wonders, taking his wild and woolly mullet and the proceeds from his record and disappear quietly from the scene.

But Billy didn’t go anywhere. He continues to record and tour, and yet the music stuff is almost a sideline these days. Now he’s the star of a series that’s in its fourth season, and even if “Doc” airs on Pax, the nichiest of networks, the longevity is rather impressive. And after you catch a few minutes of the show, a trifle puzzling.

The gentle, modestly diverting series has cast Cyrus as a good old boy from Montana who happened to pick up a physician’s credentials along the way. And to give the premise a tidy fish-out-of-water tweaking, they’ve picked him up and plopped him down in the Big Apple, where Dr. Clint Cassidy’s homespun bedside manner proves to be a hit with the hard-bitten locals. Cyrus’ best acting move is a caring stare, but he’s not asked to do too much here.

Sunday at 8, in an episode dubbed “Rules of Engagement,” there’s the usual jumble of plot lines. In the uneven segment that gives the episode its title, Capt. Doss (Kevin Jubinville) bumbles about trying to arrange the perfect setting in which to propose to clinic receptionist Tippy (Paula Boudreau). Elsewhere, an underwritten attempt at comic relief has Officer Nate Jackson (Richard Leacock) trying to repair a toilet.

And in a centerpiece designed to give those heartstrings a good plucking, a boy (Joseph Marrese) faced with progressive hearing loss gets some perspective from Dr. Clint and a real-life Broadway performer with his own hearing disability (Troy Kotsur from “Big River”). And darned if, after a few shaky scenes, the last story doesn’t manage to save the show.

Even Capt. Doss, wooden to the point of petrifaction early on, pulls it together for a warmly satisfying closing scene.

As long as “Doc” keeps the strength of the show -- its achy-breaky heart -- in good working order, Cyrus’ career prognosis is looking good.