(CNN) -- After three films and 2009's slightly lackluster spin-off ("Wolverine"), Twentieth Century Fox is hoping the "X-Men" franchise can extend into a second decade by injecting new blood and turning the clock back to the characters' younger days.
It's a strategy that paid off handsomely for JJ Abrams' "Star Trek." "X-Men: First Class" isn't in the same league, and won't generate the same excitement, but in most respects it's a solid effort that maintains the integrity of this rather earnest series.
Returning to the Nazi era that seems to exert such a strong pull on "X-Men" producer Bryan Singer, the film introduces Erik Lensherr as he's being herded away from his mother by the SS at the height of WWII. The boy's furious reaction brings him to the attention of a Josef Mengele-figure -- Kevin Bacon, initially in German -- a scientist who believes Hitler's notion of a blond-haired, blue-eyed Master Race doesn't begin to go far enough.
The next time we see Erik, the '60s are just starting to swing and he's played with welcome intensity by rising star Michael Fassbender (Rochester in this year's excellent "Jane Eyre") as an angry Nazi-hunter with potent telekinetic weapons. By now his erstwhile tormentor has reinvented himself as Sebastian Shaw, whose Hellfire Club is quietly shaping nuclear policy from backrooms and bedrooms in Las Vegas and Moscow.
Meanwhile in England, Charles Xavier (James McAvoy) is just beginning to make a name for himself and earn his professorship with his groundbreaking work on genetic mutation.
The battle lines for the X-Men haven't really changed, but not everyone has figured out on which side they belong.
Nurtured by the Establishment, Charles is soon co-opted by the CIA to help prevent Shaw and his allies from choreographing WWIII off the coast of Cuba. Arguably more true to his nature, Erik signs on too, but remains deeply cynical about how far the humans can be trusted.
A bevy of promising young actors, including Nicholas Hoult ("A Single Man"), Jennifer Lawrence ("Winter's Bone") and Zoe Kravitz ("Californication") make very 1960s-style choices about being proud of their skin color (blue, in Raven's case), and whether revolution trumps assimilation.
Any subversive hopes that "Kickass" writer-director team Jane Goldman and Matthew Vaughn would inject some levity into the proceedings peter out pretty quickly. A wittier, less vapid actress than January Jones might have vamped it up a bit as Emma Frost, a telepath who models a series of scanty go-go outfits but turns to ice when you get under her skin.,
There's a nice gag when the first gen-Xers come up with their "stage names" during something that seems suspiciously like a drunken frat party (not that we see them imbibe), but mostly the movie takes itself a shade too seriously. Except for the guy who learns how to fly by screaming, nobody seems to be having much fun -- and that includes the audience.
So far as action goes, it's all CGI pie- (or submarine) in-the-sky stuff, impressive up to a point, but never truly suspenseful. The fate of the world may hang in the balance, but we have a fairly good idea of how it's going to turn out. One genuinely mind-bending death scene apart, Vaughn's clunky staging of the green screen sequences doesn't help -- unless those echoes of "Mighty Morphin Power Rangers" are intentional?
But that's too harsh an assessment of a reasonably smart, fairly engrossing Marvel movie. If you stuck through "Wolverine," you'll be relieved that the Origin series seems back on an even keel.
For the rest, what may be most noteworthy is the consecration of a magnetic new star. The name is Fassbender: Michael Fassbender, and once he's got that pesky Irish brogue under control he should have an exciting career ahead of him.