The cheese is thick and it smothers everything in “The Boy Next Door,” but it’s never quite gooey or spicy enough.

You want an erotic thriller in which a hunky 19-year-old seduces a mom twice his age – and then obsessively stalks and threatens her – to be as over-the-top as possible. If you’re going to make an R-rated version of what is essentially Lifetime movie material, as director Rob Cohen has done here, you don’t want anything resembling restraint.

“The Boy Next Door” has its share of so-bad-they’re-good moments – and details, and chunks of dialogue – but not nearly enough. Mostly, they’re just bad. And it had such potential too, starting with the casting.

Jennifer Lopez stars as the WASPily named Claire Peterson, the hottest high school English teacher in the San Fernando Valley. How she finds time to blow out her hair and apply full makeup every morning – complete with smoky eyes and glossy lips – while also serving as a single parent to her teenage son, Kevin (Ian Nelson), is the film’s real mystery. At night, she lounges around in flimsy tank tops and teddies that cling to the actress’ world-famous posterior. Buffed and polished to a high sheen, J-Lo is 45 and has never looked better – and that’s actually part of the problem. A woman who’s a little more vulnerable, and a little less of a force of nature, might have been a more believable mark.

Claire has been lonely lately since separating from her philandering husband, Garrett (John Corbett). And the sweet but slightly nerdy Kevin could use a strong male figure around, too. So it’s perfect timing when the handsome and muscular Noah (Ryan Guzman) moves into the house next door to help his ailing uncle (who distractingly resembles Johnny Knoxville in his “Bad Grandpa” makeup). We actually see his biceps before we see his face. But there’s so much more to him than just his looks; in the screenplay from first-timer Barbara Curry, he’s hilariously too good to be true.

Noah fixes cars and cleans out storm drains. (The first thing he repairs is Claire’s broken garage door. How’s that for a sexual metaphor?) He can beat up the bullies who antagonize Kevin and give the kid enough confidence to ask out the prettiest girl in school. But he’s also a scholar, and can quote extensively from “The Iliad.” (The way this classic piece of literature is used throughout the film inspired unintentional laughter during the screening I attended.) And so, at age 19, he finagles his way into Claire’s English class, having never graduated from high school because of his troubled, orphaned past.

On the one night a year that it rains in Los Angeles, after a couple glasses of wine, Claire gives in to Noah’s flirtations and sleeps with him in a scene that’s admittedly quite steamy, despite Lopez’s no-nudity clause. The next morning, though, as she’s gathering her things and preparing to do the (quick) walk of shame, Noah’s clingy, intense freak-out should be her first clue that something is a little off with this guy.

Guzman, a veteran of the “Step Up” franchise, may know the moves here, too, but never sells them convincingly. There’s something too boyish about his looks and underdeveloped about his craft. He’s never truly menacing, which depletes this erotic thriller of much of its thrills, and he ends up being thoroughly outmatched by the charismatic Lopez at every turn.

From here, there are multiple instances of elaborately threatening behavior which should be enough cause for Claire to go to the police, but then we would have no movie. Instead, we watch as she scrambles and fumbles in hopes of appeasing this psycho – and inadvertently places herself and her family in further danger. Cohen directed the first “Fast and Furious” movie from 2001, and he gets the chance to insert one decent car chase as a reminder of what he’s capable of doing with more lively material.

Only the insane (and insanely violent) climactic showdown, in a burning barn, of all places, finally gives the people what they want. You’ll howl, you’ll squirm, you’ll applaud with disgusted glee – and you’ll wish that the rest of the film were that much fun.

Christy Lemire

Christy Lemire is a longtime film critic who has written for RogerEbert.com since 2013. Before that, she was the film critic for The Associated Press for nearly 15 years and co-hosted the public television series “Ebert Presents At the Movies” opposite Ignatiy Vishnevetsky, with Roger Ebert serving as managing editor. Read her answers to our Movie Love Questionnaire here.

The Boy Next Door

Drama
star rating star rating
91 minutes R 2015
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