Yet another attempt to turn a popular fantasy book series into a movie franchise that fails miserably, “Seventh Son” wastes the talents of people like Jeff Bridges and Julianne Moore in a tediously familiar tale involving witches, shape-shifters and their heroic opponents that relies heavily on CGI transformation scenes for effect. It doesn’t take long for a viewer to realize that this “Son” is stillborn.

The movie, directed without much panache by Sergei Bodrov (who fared far better on his home territory with “Mongol”) is very loosely derived from “The Spook’s Apprentice” (2004), the first book of Joseph Delaney’s “The Wardstone Chronicles” (published in this country as “The Last Apprentice”), which grew to thirteen volumes before ending last year. Set in the north of England during medieval times, the series followed the development of Tom Ward, a twelve-year old farmboy and the seventh son of a seventh son, who was taken on as an apprentice by John Gregory, a so-called Spook who does battle with all creatures of The Dark; the first book dealt with Tom’s initial experiences in his new role, including a confrontation with a witch called Mother Malkin and a girl named Alice who’s related to her.

Delaney’s rather simple story has been turned into an overblown behemoth by scripters Charles Leavitt and Steven Knight. Tom is no longer a boy, but a strapping young man (Ben Barnes) who yearns to leave the farm and doesn’t much object when he’s virtually sold to Gregory (Bridges). (He also has visions of future events, a circumstance that will eventually be explained by the background of his mother, played by Olivia Williams.) The Spook, portrayed as a drunken old fellow who can still punch out much more formidable foes, needs a new apprentice because his former one (Kit Harington) has just been killed in battle by Malkin (Moore), here the Queen of Witches imprisoned years before by Gregory but recently escaped from her underground cavern as a result of the incipient appearance of the Blood Moon, a centennial phenomenon that gives her special powers. Malkin also has the ability to change into a dragon, and does so with depressing frequency to give the visual effects team something to play with.

But she’s not the only shape-shifter. She has a coterie of helpers who can do so as well—one turns into a leopard, another into a bear, a third into a dragon of different stripe from Malkin’s. What little plot there is consists of some perfunctory training sequences for the apprentice before he and Gregory set off in pursuit of Malkin, accompanied by the Spook’s ugly but loyal servant Tusk (John DeSantis). In the process they meet up with Alice (Alicia Vikander), the beautiful, spunky daughter of Milkin’s devoted assistant Bony Lizzie (Antje Traue). Alice seems to possess no witchy abilities but easily seduces Tom with her coquettish charm as he and the Spook wend their way through a series of tiresome adventures prior to a final confrontation with Milkin and her confederates, filled with CGI transformations, falling pillars and seemingly endless waves of mayhem.

Probably no young actor could have invested Tom with sufficient charisma to make “Seventh Son” seem like something other than one more dismal modern retread of the sort of boys’ adventure yarns Ray Harryhausen used to turn out with stop-motion creatures, but bland Barnes (Prince Caspian in the “Narnia” pictures) certainly doesn’t do the trick. Perhaps to make up for his young co-star’s dullness—but more likely because it’s just his way—Bridges gives another of his way-over-the-top turns, acting semi-looped throughout and delivering his lines mushily as he contorts his lower jaw into what appears to be a grotesque underbite. Moore’s presence promises far more than it delivers: in her human form, the Queen Witch is just an icily unemotional woman with extra-long fingers, and she too often changes into beast form to allow the actress much chance to do anything distinctive—just as her recent turn in “Mockingjay” hamstrung her. Vikander is pretty but not especially engaging as Alice, and Williams has a nice maternal air, while Harington, after his death scene in “Pompeii,” gets another one here: maybe a pattern is emerging.

But all the cast play second fiddle to the effects, which can be described as fairly standard-issue. They’re integrated reasonably well with the live-action footage shot in the oppressively dark, gloomy tones thought appropriate to medieval times by Newton Thomas Sigel, whose visuals have been punched up with 3D enhancements that no one could describe as subtle. But the compositions do the best they can with Dante Ferretti’s dank production design, the obvious model work, and Jacqueline West’s uninspired costumes. Marco Beltrami’s score, at least when heard over IMAX speakers, is bombastically overpowering, and the sound overall is loud to the point of discomfort.

Life on a medieval farm was undoubtedly hard, but it might have been better for all of us if Tom Ward had just stayed home and tended the pigs.