Call "I Am Number Four" formulaic and derivative, and odds are its creators will congratulate themselves on a job well done.

The young-adult novel on which it's based was produced in a "fiction factory" run by disgraced faux-memoirist James Frey - a company intended to churn out books that become pop-culture franchises like "Twilight."

The aliens-among-us plot of "Number Four" certainly offers many of the elements associated with such blockbusters. Its hero, John Smith (Alex Pettyfer), is a good-looking teen with a secret (he's an alien, one of his world's few survivors) whose romantic longings are thwarted by the outside world.

Pursued by evil aliens who colonized his home planet, he's under intense pressure to conform, not making waves or even friends. Above all, John's warrior-protector father figure (Timothy Olyphant of "Deadwood") expects him to keep his face off the Internet. You can practically hear the gasps of every Facebook-addicted teen in the theater (or see their eyes roll) when Olyphant lays down that law.

"Number Four" cops from teen fictions older than the vampire craze, though. Like Peter Parker, John suddenly finds himself in a pubertylike transformation granting him special powers that sometimes manifest themselves in public, leading to awkward scenes with classmates. How's a guy supposed to explain that his palms start to glow when classroom lights dim for an educational film?

There isn't a single new idea in the film, save perhaps for one that is never explained: For some reason, John and his fellow Lorien refugees (the other aliens are scattered across the globe) can only be killed by their Mogadorian pursuers in a certain order. (As you may guess from the title, numbers one through three have already bitten the dust.) Why is this? If there is an answer, it's being withheld for future installments.

But originality or no, the filmmakers (who collaborated on another alien-teen yarn, "Smallville") generate enough pizzazz to make "Number Four" a fun diversion whose clichés are too inevitable to complain about.

If some cast members exhibit less talent than others, they are uniformly easy to look at, especially Dianna Agron ("Glee"), as the shutterbug classmate who steals John's heart.

"We don't love like the humans," Olyphant tells his protégé moodily. "With us, it's forever." And if you think that line is carefully tailored to tug at teen-girl heartstrings, just wait until the adorable puppy dog turns into a massive CGI beast to defend its master from alien dragons. The movie's action is pretty fun once it gets going, actually, with stylish effects work, a zippy pace and - what's this? - the arrival of a butt-kicking Australian blonde who makes Agron suddenly look plain.

Will there be a "Twilight"-ish rivalry between these two girls for our hero's heart? If the sequel-hungry producers have their way, you can tune in next year to find out.

"I Am Number Four"

Our grade: C

Genres: Science Fiction, Thriller, Action

Running Time: 110 min

MPAA rating: PG-13

Release Date: Feb 18, 2011