There's a lot going on in "I Am Number Four," and very little of it makes sense.
Perhaps the yelling, screaming, chasing and exploding are meant to hide a poor excuse for a plot in a movie that seems to have been made for the small screen. It's far below the quality of most science-fiction offerings (the ghastly "Skyline" excluded) and seems to have been developed for the young adult/teen audience, which deserves better.
John (hottie Alex Pettyfer, soon to be seen in "Beastly") is a tan, toned, athletic type who doesn't stay in one place very long. That's because he's from another planet and is gaining special powers as he matures. He is hiding along with his caretaker/guide Henri (Timothy Olyphant, who starred in last year's really good science-fiction thriller "The Crazies"), who sees that his younger charge remains safe from another race of aliens. The alien goons are an icky-looking lot with gills on their faces (they do have great taste in attire, though, and wear long black leather coats).
John is among a handful of teen aliens who are hiding on Earth. One by one, the aliens are killing them off. John, of course ... well, you already saw the title.
Henri decides that John should stay undercover (not unlike the situation in the "Big Momma" movie on a neighboring screen, only without the fat suit), so John enrolls in high school. The powerful jocks take quite a dislike to him for befriending the wrong people: a girl named Sarah (Dianna Agron, television's "Glee") and Sam (Callan McAuliffe, who was terrific in last year's under-seen "Flipped"), a bullied kid who believes in extraterrestrial life.
Henri warns John not to get caught up with a girl and drawn into all the trappings of his fake life. But John can't help enjoying everything about Sarah, from her photography to the banter at her family dinner table.
There's a little bit of "Pinocchio" here, what with John wanting to be a real boy (which is even referenced in the dialogue), and quite a bit of "Lassie," because John is protected by a beagle who suddenly appears at his home.
After a battle scene that's entirely too long and simply preposterous, there's a set-up for a sequel. Let's hope the box office doesn't create an excuse for this to drag on any longer.