“I Am Number Four” is a frustrating film.

There are elements of a good film in there. The underused Timothy Olyphant is always a pleasure to watch, and the film’s action scenes are fantastically directed by D.J. Caruso. Unfortunately, entirely too much of the film can easily be described in one word: silly.

Possibly the film’s silliest aspect is its plot, which is lifted from the young adult novel of the same name. It focuses on Number Four (Alex Pettyfer), a member of the Garde, the only survivors of an alien race called the Loriens who have been hunted to Earth by the nefarious Mogadorians, another alien race intent on destroying them. Yes, the names of the alien races are actually that ridiculous and are made even more so thanks to the real-world context in which they’re presented.

Unfortunately, the Loriens can only be killed in chronological order, and Number Four is the next in line. If that wasn’t enough, he’s recently been relocated to the ironically named Paradise, Ohio, which the film is clever enough to have its characters nickname Ironic, Ohio. (No, seriously.) It’s in Paradise that Number Four, renamed John Smith, meets the artsy Sarah (Dianna Agron) and falls madly in love.

This isn’t to say the story doesn’t have one or two good elements as well. John also develops a friendship with the nerdy Sam (Callan McAuliffe) who gives the film a much-needed dose of humanity. This small bright spot in the film is overshadowed by the more laughable aspects of the rest of the plot.

The film’s actors all deserve some degree of credit, if only for the fact they can deliver lines about evil Mogadorians with a straight face. Nonetheless, the film is almost universally poorly acted.

As mentioned above, Olyphant elevates every scene he’s in, and McAuliffe is charming and relatable in a way that the rest of the cast never quite manages. Pettyfer isn’t much of a leading man, coasting almost entirely on his good looks and ability to brood convincingly. Meanwhile, Agron’s artsy kindred spirit is lifted from a dozen other teen movies, and watching her struggle to bring something new to the character gets old fast.

The fact that much of the film is devoted to Pettyfer and Agron’s slowly developing romance only makes matters worse. The high school machinations that make up too much of the film’s runtime aren’t even close to being original and become even more frustrating when compared to the other half-dozen or so slightly more interesting plot threads the film throws into the mix.

Despite everything that’s terrible about it, the film’s action scenes are undeniably impressive. The opening sequence boasts a parkour-style chase that sets the bar extremely high for the rest of the film, and the final half hour is an inventive and memorable showdown that more than lives up to expectations. Director D.J. Caruso, fresh off 2008’s action-packed “Eagle Eye,” stages the interlocking fights that comprise the film’s climax with remarkable precision and confidence, making the geography of each fight clear while installing a tangible sense of tension in each battle.

Even with all of its shortcomings, “I Am Number Four” is still probably worth seeing. The camp value of hearing the actors describe the film’s backstory can’t be properly reflected in text, and the acting can get hilariously bad. When Pettyfer’s dull performance wears too thin for entertainment value, there are the small moments that are genuinely good, from McAuliffe’s wonderfully played story arc to the action scenes sprinkled throughout the picture.

While it’s a deeply flawed film, it’s sure to be a huge hit that will spawn a small collection of sequels, and I’d be lying if I said I wasn’t looking forward to seeing a bigger and hopefully better installment in this franchise.