Lopez plays Claire Peterson, a woman whose marriage is foundering. Claire evidently isn't stricken by shyness; she's dressed to put her body on display even when she's just hanging around the house.
Not surprisingly, Claire attracts the attention of Noah Sandborn (Ryan Guzman), a high-school senior who's new to the neighborhood and who's taking care of a sick uncle who happens to be Claire's next door neighbor.
It doesn't seem to have bothered anyone that Guzman is 27, and looks it. He's a classmate of Claire's teen-age son (Ian Nelson), a kid who actually looks like he might still be in high school.
You may want to think of Noah as a psychotic version of Eddie Haskell of Leave It to Beaver fame. At first, he's incredibly helpful to Claire, who's trying to get by without the presence of her estranged husband (John Corbett).
Corbett's character knows he made a mistake by cheating on his wife. He wants to return home. Not so fast, says a wary Claire.
In a moment of desperation and horniness, Claire sleeps with Noah, who immediately develops an obsession with her. The filmmakers do everything they can to give the scene some soft-core gloss. All that's missing is a label: MAJOR SEX SCENE IN PROGRESS.
Did I mention that Claire is a high school teacher who specializes in the classics and that Noah worms his way into the class so that he can cement his relationship with Claire and show off his mastery of Homer?
Once Claire comes to her senses, she wants nothing more to do with Noah, but he won't take "no" for an answer. He reveals himself as a manipulative and ultimately violent stalker who threatens to ruin Claire's life.
Eventually, Claire turns for help to her BFF, the schools vice principal played by Kristin Chenoweth.
All of this builds toward a violent showdown that's so preposterously gruesome, it provoked a few laughs at a preview screening.
Despite the addition of a wafer-thin psychological explanation for Noah's behavior, The Boy Next Door offers little by way of big-screen pleasure -- unless you want to ogle Lopez or the hunky Guzman.
The Boy Next Door may be trying to be an over-the-top thriller, but it winds up scraping the bottom of the big-screen barrel.