It was inevitable, one supposes, that after the sequels, imitations and remakes there would come a prequel to “The Texas Chainsaw Massacre,” Tobe Hooper’s trend-setting 1974 high-carnage shocker; it’s the same pattern that led to the TV movie “Psycho IV: The Beginning,” back in 1990, three decades after the appearance of Hitchcock’s original. And here it is, coming just a bit over three decades after Hooper’s film.

What wasn’t inevitable is that “The Texas Chainsaw Massacre: The Beginning” would be so tedious. The movie does offer a brief explanation of how the mayhem begins–it turns out that old Leatherface was a deformed infant born in a slaughterhouse (where he later worked), adopted by the local weirdos, tormented by kids at school, and then moved to kill his nasty boss when the slaughterhouse closes, at the climax of which gory murder (done with a sledgehammer) he finds his weapon of choice, the good old chainsaw, that he eagerly takes up. So poor little Leatherface is a victim of abuse–misunderstood, as his adoptive daddy will say in the movie. Just what we needed–psychobabble–plus the intimation that a visit to a shrink might have avoided the resultant unpleasantness.

But after this “prologue,” things get worse: the movie just turns into a recycling of the 1974 original (and the not-bad remake of 2003) as three of four young travelers–brothers Eric and Dean (Matt Bomer and Taylor Handley) and Dean’s girlfriend Bailey (Diora Baird)–are captured by Leatherface’s cannibalistic adoptive dad (R. Lee Ermey), who’s impersonating the dead sheriff, and dragged back to the homestead to be tortured and eviscerated. Eric’s squeeze Chrissie (Jordana Brewster) is the character who remains free to slink about the house of horrors and try futilely to rescue her friends. One more character is introduced for gore’s sake–a scuzzy motorcyclist. And there’s room for lots of half-humorous scenes involving the twisted family and their flesh-eating ways, including a dinner sequence guaranteed to put you off your popcorn.

There’s nothing new in all this, and one quickly gets the feeling that the filmmakers have gone to the same well far too often. Director Jonathan Lieberman shows none of the pizzazz that Marcus Nispel exhibited in the 2003 remake (or Hooper in the original, of course), and so the movie quickly becomes extraordinarily dull despite the periodic bloodlettings. There’s no tension here, only the cheapest of shocks (usually provided by quick bursts of music and sound rather than any striking images) and an abundance of skewered skin, broken bone and internal gristle, as well as plenty of piercing screams. And given that this is a prequel, and we know in advance the villains can’t get caught or the victims survive, there’s certainly no suspense, only ninety minutes of lip-smacking sadism. This is entertainment?

Among the cast, only Ermey stands out. He’s a total hambone, but he has the few vaguely amusing lines the script has to offer, and he obviously relishes them. As to the youngsters, they have all the depth and personality of bits of beef ready to be shishkabobbed. And Andrew Bryniarski, reprising his Leatherface from the 2003 movie, just hulks around, as colorless a masked slasher as ever graced the screen.

From a visual standpoint, “The Beginning” tries to ape the faux gritty-music video style that Nispel offered, but merely looks dim and grungy. And Steve Jablonsky’s overblown score is deafening rather than supportive.

If you want to see a quartet of young people sliced, diced and otherwise brutalized in grisly detail, this is the dish for you. And if you find it to your taste, it’s probably you, not Leatherface, who really need therapy.