Production has begun on the fantasy action adventure flick Seventh Son, and with that announcement comes an official synopsis.  Briefly: Jeff Bridges plays a knight who had imprisoned an evil witch (Julianne Moore), but then she escapes and plans to do evil witchy things.  The knight is forced to take on an apprentice (Ben Barnes)—the seventh son of a seventh son—and only has until the next full moon to get the kid up to snuff.    The movie is based on The Spook's Apprentice, the first novel in Joseph Delaney's young adult book series, The Wardstone Chronicles, which has franchise potential because of course it does.  Thankfully, it's got a good cast on board, which also includes Olivia Williams and Kit Harington.Hit the jump for the press release, which includes the synopsis.  Legendary Pictures made a brief presentation for the film at last year's Comic-Con so it's possible we might see another appearance at this year's Con.  The press release doesn't include a release date, but Box Office Mojo is listing the film for February 15, 2013.Here's the press release.  I've bolded the synopsis:

PRODUCTION BEGINS ON "SEVENTH SON"

FOR WARNER BROS. PICTURES AND LEGENDARY PICTURES

Jeff Bridges, Julianne Moore and Ben Barnes Lead the International Cast.

BURBANK, CA, March 26, 2012 — Principal photography is underway on Warner Bros. Pictures' and Legendary Pictures' fantasy action adventure "Seventh Son." Shooting began on March 19, under the direction of award-winning filmmaker Sergei Bodrov, director of the Oscar®-nominated foreign language films "Mongol: The Rise of Genghis Khan" and "Prisoner of the Mountains." "Seventh Son" stars Academy Award® winner Jeff Bridges ("Crazy Heart," "Iron Man"), Oscar® nominee Julianne Moore ("Far From Heaven," "The Hours"), and Ben Barnes ("The Chronicles of Narnia" films).

In a time long past, an evil is about to be unleashed that will reignite the war between the forces of the supernatural and humankind once more. Master Gregory (Jeff Bridges) is a knight who had imprisoned the malevolently powerful witch, Mother Malkin (Julianne Moore), centuries ago. But now she has escaped and is seeking vengeance. Summoning her followers of every incarnation, Mother Malkin is preparing to unleash her terrible wrath on an unsuspecting world. Only one thing stands in her way: Master Gregory.

In a deadly reunion, Gregory comes face to face with the evil he always feared would someday return. Now he has only until the next full moon to do what usually takes years: train his new apprentice, Tom Ward (Ben Barnes) to fight a dark magic unlike any other. Man's only hope lies in the seventh son of a seventh son.

The film's international cast also includes Alicia Vikander ("The Crown Jewels"), Antje Traue ("Pandorum," upcoming "Man of Steel"), Olivia Williams ("Hanna") and Kit Harington (HBO's "Game of Thrones").

Bodrov is directing the film from a screenplay by Matt Greenberg, Charles Leavitt and Steve Knight, based on the book The Spook's Apprentice by Joseph Delaney. "Seventh Son" is being produced by Basil Iwanyk ("The Town," "Clash of the Titans" upcoming "Wrath of the Titans"), Thomas Tull ("Inception," "The Dark Knight" upcoming "The Dark Knight Rises") and Lionel Wigram ("Sherlock Holmes: A Game of Shadows," the "Harry Potter" films). The executive producers are Jon Jashni, Brent O'Connor and Alysia Cotter, with Jillian Zaks and Erica Lee serving as co-producers.

The behind-the-scenes team collaborating with Bodrov includes director of photography Newton Thomas Sigel ("Drive"); three-time Oscar®-winning production designer Dante Ferretti ("Hugo," "Sweeney Todd: The Demon Barber of Fleet Street," "Aviator"); Oscar®-nominated editor Paul Rubell ("Collateral," "The Insider"); Oscar®-nominated costume designer Jacqueline West ("The Curious Case of Benjamin Button," "The Social Network"), and Oscar®-winning visual effects supervisor John Dykstra ("Spider-Man," "Spider-Man 2").

"Seventh Son" will be filmed entirely on location in Vancouver, British Columbia, Canada.

A presentation of Warner Bros. Pictures and Legendary Pictures, "Seventh Son" will be distributed worldwide by Warner Bros. Pictures, a Warner Bros. Entertainment Company.