There hasn’t been a really big dragon movie for a long while if you discount (as most viewers understandably did) 2000’s “Dungeons and Dragons,” which featured altogether too many of the flapping creatures; so Rob Bowman’s “Reign of Fire” may fill a niche need. The last memorable entry in the category was probably “Dragonheart” back in 1996–also directed by a fellow named Rob (Cohen, in that case). This time around, however, the dragons involved aren’t the sweet, helpful sort of critters that Drogo was in that flick–they’re more like Godzilla (or since they fly, maybe like Rodan), very nasty and destructive. And they don’t speak in Sean Connery’s gruff but dulcet tones; they just shriek occasionally, usually as they’re about to fry the surroundings or gobble somebody up.

Contrary to what you might expect, “Reign of Fire” isn’t a medieval myth movie; it’s actually set in a post-apocalyptic near-future, akin to the bleak visions found in innumerable “Mad Max”-themed potboilers over the past few decades. The rather silly premise is that the beasties were awakened by excavations in England; apparently they’d been buried before Noah collected two of each species for his ark and so they didn’t make the trip, but they survived nonetheless. Now they’ve been released with apparently only one aim in their puny brains: the wholesale eradication of humanity. Happily a much-diminished mankind still has a few stout defenders. Those we meet in this film include Quinn (Christian Bale) a scraggly, well-muscled British “fireman” (a guy who puts out blazes the monsters start up); Quinn, we’re told, was a precocious kid present when the first of the dragons was unearthed during a London subway project (shades of “Quatermass and the Pit,” a.k.a “Five Million Years to Earth,” a much better film) and his mother killed in the process, and now he’s brought a small community (including a bunch of “Oliver Twist”-like orphan kids) together in an old Northumbrian castle to survive against the horde. But Quinn’s small realm is invaded by a brigade of Americans led by a husky, take-no-prisoners, self-styled dragon-slayer named Van Zan (Matthew McConaughey), accompanied by a svelte, heroic helicopter pilot (Izabella Scorupco). Van Zan swings a mighty mean axe, and he’s devised a technique involving the chopper and some gung-ho parachutists whereby dragons can be trapped and zapped. But he has a larger mission: to travel to London and destroy the patriarch dragon (indeed, the only male of the bunch), thereby ending the plague for good.

Though there’s a smidgen of snappy patter and half-comic derring-do in “Reign of Fire” (much of it provided by Quinn’s buddy Creedy, played by Gerard Butler with a thick brogue, and a brief low-tech recapitulation of “Star Wars” for Quinn’s orphans), the makers mostly play things pretty straight–which is, unfortunately, a mistake. Quite simply, the script concocted by Gregg Chabot, Kevin Peterka and Matt Greenberg (the first two neophytes who have obviously watched too many 1950s B movies, the third a “veteran” responsible for such gems as “Halloween H20” and “The Prophecy II”) is a “Jaws” ripoff no less ludicrous than “Orca–Killer Whale,” and Bowan (who helmed many “X-Files” episodes, as well as the feature) works so hard at creating a gloomy, doom-laden atmosphere that he largely ignores such minor matters as coherence, clarity and energy. The result is that the picture is not only silly but narratively muddy and visually murky. The cast suffers badly. A buffed-up McConaughey looks and acts like a Bruce Willis cartoon; when, toward the close, he plays a scene that recalls Robert Shaw’s final moments at Quint, he’s so rabid that, combined with the poor writing and slovenly effects, you almost hope that the bald pate and bristly beard will keep him from being recognized. Bale, who’s shown great skill in films like “American Psycho,” is reduced to a scowling caricature. Scorupco is a nonentity as the chopper maid, and her romance with Bale’s Quinn is so abrupt and unconvincing that it seems an unnecessary afterthought. Butler gets a few chuckles, but everybody else in the picture, including Scott James Moutter as Quinn’s young lieutenant and surrogate son, look like understandably uncomfortable refugees from a rag-pickers’ convention. To add to the sorry litany, Adrian Biddle’s cinematography is as uninteresting as the rust-and-debris production design by Wolf Kroeger, and Edward Shearmur’s score sounds purely generic. The dragons are decently enough rendered, but they make curiously uninteresting foes.

“Reign of Fire” showcases, on several occasions, a credo instilled in his orphan wards by Quinn: “When you’re awake, keep both eyes on the sky; when you’re asleep, keep one eye on the sky.” We can now add a third element to the recipe: When this movie is showing, keep both eyes closed.