The advertising come-on that “I, Frankenstein” comes from the folks who brought you the “Underworld” movies is hardly accurate (the only real connection are that Kevin Grevioux wrote the graphic novels both are based on and has small roles in each, both share producers, and Bill Nighy plays the chief villain in both). But it can be said that the new movie follows the template of the earlier series almost slavishly. The background is a “war” between rival supernatural forces of which humans are unaware: in “Underworld” it was vampires and werewolves, while here it’s gargoyles and demons. And a single heroic figure emerges to try to end it once and for all. In “Underworld” it was the disaffected vampire Selene, played by slinky Kate Beckinsale in some tight black leather duds. Here it’s Aaron Eckhart in tattered clothes and a grubby hoodie. Many in the audience, particularly males, will not find this a satisfactory exchange.

Eckhart plays Dr. Frankenstein’s monster—we get a brief synopsis of Mary Shelley’s novel as a prologue narrated by him—a couple of centuries on. (What he’s been doing since 1795 is never made clear.) But suddenly he becomes the focus of the conflict between the good, angelic gargoyles led by Queen Leonore (Miranda Otto), who eventually names him Adam, and her chief lieutenant Gideon (Jai Courtney) and the wicked demons, or fallen angels, led by the nefarious Naberius (Nighy) and his band of “Matrix”-suited minions. The reason is that Naberius has long been nursing a scheme to collect human cadavers, reanimate them and have them possessed by “descended” (that is, evaporated) demons so as to assemble an army that will conquer the world. Frankenstein’s creation, or at least his notebook, will hopefully be the key that will allow Naberius’ hand-picked reanimation expert, pretty blonde electrophysicist Terra (Yvonne Strahovski) and her loyal lackey Karl (Nicholas Bell) to finally get the plan on track.

The upshot is that Leonore and Gideon save Adam from Naberius’ clutches, but remain doubtful of his usefulness as an ally until, in the final reel, he emerges as mankind’s ultimate protector—the result of his connection with Terra, who becomes his ally and (dare we say it?) romantic interest. It should surprise no one that the evil demon plot is foiled and Leonore, and the God she serves, smile beatifically upon both of them—though it’s hard to discern a real smile on the face of the stony flying gargoyle into which she transforms when doing battle.

It seems to have occurred to none of the filmmakers that Naberius’ goofy scheme pretty much replicates the idiotic one undertaken by Eros (Dudley Manlove), the alien invader, in Ed Wood’s “Plan 9 from Outer Space,” widely celebrated as one of the worst movie of all time. And it can be argued that despite its far costlier effects, “I, Frankenstein” falls into the same category. Its deadly seriousness in the service of a ludicrous plot mirrors Wood’s clueless attitude, the dialogue is equally risible, and the acting is uniformly awful. Eckhart, who’s forced to narrate great swaths of the picture, keeps a straight face throughout the manic enterprise, but otherwise is an embarrassment, while Strahovski seems to have difficulty reciting English dialogue, as well as acting at all. Nighy seems to be the only person in sight who realizes—as he did in the “Underworld” series—the inanity of the proceedings. He responds once more with a snarling, over-the-top turn that’s the polar opposite of the charming ones he can produce in pictures like “The Best Exotic Marigold Hotel” “About Time.” But at least he gets to wear a simple suit, unlike the ancient Greek-style garb that Otto and Courtney are compelled to parade around in.

Visually the movie is pretty much a mess. Director Stuart Beattie and cinematographer Ross Emery keep the camera moving as much as possible, creating a seasickness effect, especially when the special effects—demons exploding into fiery globs, gargoyles ascending into the clouds via shafts of blue-silver light, not to mention all the transformations and explosions—kick in. (It has to be said that the gargoyles and demons come off very badly in close-up, looking like Harryhausen rejects, and the collapsing building sequences aren’t appreciably superior to bad modeling work.) The score by Reinhold Heil and Johnny Klimek is ear-splitting, as are the sound effects—they’re so loud they might actually keep you awake as the narrative drags on.

“I, Frankenstein” is truly a terrible movie. At one point Adam, in dispatching a foe, says, “Descend in pain, demon.” The message of the makers to their audience might as well be, “Watch in pain, human.”