In "Monsters," a couple must pass through an "infected zone" teeming with giant alien creatures in order to return to America.

“Monsters” could be described in short as “District 9” in Mexico, except with amphibious giant octopi as the aliens. This is a bit of a simplification but still manages to capture the socially conscious sci-fi subgenre into which “Monsters” neatly fits. Despite the film’s gripping sci-fi premise, it flounders because of its excessive focus on the limp romantic relationship between the two leads.

Six years before the story begins, a NASA space probe breaks up upon re-entry over Mexico, resulting in over half the country being quarantined and designated as an “Infected Zone.” The plot, at least for the middle third of the film, focuses on the romantic development between the two main characters Samantha Wynden (Whitney Able) and Andrew Kaulder (Scoot McNairy), the latter of whom is sent by his wealthy and powerful boss—Samantha’s father—to ensure her safe passage home. After failing to make the last ferry back to the U.S., the two rashly choose to take their chances on foot through the infected zone.

Excelling cinematographically, the film manages to find a balance between artsy composition and jittery sci-fi camera work. Perhaps as part and parcel of inserting an emotional drama into a sci-fi thriller, there are numerous sweeping panoramic shots. But in the more action-packed scenes, director Gareth Edwards engages in the shaky-camera technique popular in action thrillers such as the “Bourne” trilogy. When the monsters—which are gruesomely rendered in CGI—are on screen the film effectively engages the viewer. However, the tempo lags throughout much of the movie due to the contrived romantic tension supposedly driving the plot through the less suspenseful sections.

Certainly, even in a sci-fi thriller, it is necessary to provide motivation for the characters—unfortunately, the blossoming sexual tension between Able and McNairy’s characters falls completely flat due to the leads’ emotionally drained acting. McNairy, who as Kaulder fills the role of the mean-spirited and culturally ignorant American, portrays little emotional affect, resulting in a character both perennially annoyed and lacking in depth. When sitting around the fire discussing the nature of the United States’ response to the alien outbreak with their Mexican guides, Wynden rejoinders a comment made about the wall along the border with, “Yeah, it’s like we’re imprisoning ourselves... Yeah.” Able delivers the line like a valley girl, which only serves to undercut the film’s attempt at meaningful social commentary.

The filmmakers’ engagement in real-world issues is often scattershot. Touching on topics such as spectatorship, racism, inequality, and immigration, the motif returned to most often is that of America’s tendency to shoot first and ask questions later. When speaking of the aliens, a guide says, “If you don’t bother them, they don’t bother you. When the American planes come the creatures get mad. They go crazy.” But even this theme is inconsistently applied, as at points throughout the movie the creatures appear to be attacking unprovoked—the guide himself is killed for no reason shortly after delivering that line of dialogue.

Though their intersection is sometimes forced, the combination of cinematography and social commentary culminates in many of the film’s most effective moments. For example, as a transition between scenes the camera lingers momentarily on a small child sitting in the window of a shack, with a large machine gun leaning against its wall. The omnipresence of violence is tied into the increasing integration of the monsters into Mexican culture—a public mural in the background of a brief scene depicts a battle between armed humans and the angry creatures. Another well-shot moment occurs when Kaulder and Wynden wander into an area of memorials adorned with candles and flowers. The camera pans to a sign saying “Stop The Attacks 5000 Dead,” indicating that the bombing of monsters is killing civilians. The symbolism becomes obvious when a moment a later a helicopter flies by, putting out the candles, resulting in a meaningful and aesthetically pleasing sequence.

Like all the best sci-fi movies, “Monsters” proves an effective vehicle for a persuasive critique of human conduct. Unfortunately, however, the film’s social mission is undermined by the weak love story. Frustration with the characters’ lack of emotional affect is only aggravated by the film’s obvious plot hole. Given that it is a story of two rich Americans finding their way back to the U.S., audiences might find themselves wondering why the characters don’t just take an airplane to fly around the infected zone. Sadly, the current age of modern aviation undercuts the over-land adventure story, resulting in a large chunk of the film feeling pointless as well as meandering.