If a curious case of déjà vu is experienced while watching the Justin Timberlake-Mila Kunis romantic comedy "Friends with Benefits," that's probably because the same premise was already covered—and better—six months ago when it was called "No Strings Attached" and starred Ashton Kutcher and Natalie Portman. Adding to the incestuous confusion is Kunis' connection to both Portman (playing the dark fowl to Portman's light in 2010's "Black Swan") and Kutcher (they co-starred together for eight seasons on "That '70s Show"). If "No Strings Attached" presented a very real, frank portrait of two young adults whose purely sexual relationship grows complicated when emotions enter the equation, "Friends with Benefits" aims to do the same thing, but with one key difference: whereas the conflicts that arose in the earlier picture were understandable based on the Portman character's fear of intimacy and relationships, Kunis' hang-ups are never understood and the barrier keeping her and Timberlake apart never feels anything less than falsely manufactured and redundant. That it is the woman in both movies (and, for that matter, in 2010's also-similar "Love & Other Drugs") who is viewed as emotionally damaged while the male suitor patiently waits for her to get her act together is a filmic tendency that's fast growing sexist, even misogynistic.

When Los Angeleno Dylan Harper (Justin Timberlake) arrives in New York City for a job interview to become art director at GQ Magazine and then promptly gets it, his vivacious executive recruiter Jamie (Mila Kunis) takes him out for a celebratory night on the town. Despite his trepidations with moving across the country, Dylan soon settles into his new life and has already made a good friend in Jamie. They are both coming off bad breakups and Jamie claims to not be interested in him as boyfriend material. Despite their obvious connection and the laundry list of compliments they shower each other with, they begin regularly sleeping with each other while continuing to spend time together as pals. Obviously they're going to start feeling more for each other, but Jamie is hesitant about admitting it for reasons unknown, and even more so when she conveniently overhears Dylan telling big sister Annie (Jenna Elfman) that "Magnum P.I. couldn't solve the shit going on in her head."

In the eyes of writer-director Will Gluck (2010's "Easy A") and novice co-scribes David A. Newman and Keith Merryman, the trouble in "Friends with Benefits" all stems from Jamie's messed-up emotional stiltedness. Dylan mostly goes along for the ride and does as she says until the exceedingly predictable third act where he must win her over once and for all. His lack of internal complexity can be attributed to script deficiencies, yes, but also to the limited range of Justin Timberlake (2011's "Bad Teacher"). Timberlake isn't an outright embarrassing actor, but it's also obvious that he's first and foremost a singer getting the chance to do some movies. Onscreen, he comes off as sort of smarmy, slightly entitled, and not terribly warm (no wonder these characteristics served him well in 2010's "The Social Network"). He additionally has trouble getting into the mind of his character and making it accessible for audiences, which is a very big problem, indeed, when you're the lead protagonist. By comparison, Mila Kunis (returning to the frothier territory of 2008's "Forgetting Sarah Marshall") is spunky and pleasant, showing up Timberlake in every scene they share while struggling to make work their uneven chemistry. Kunis' Jamie plainly states that she believes in true love and wants someone to spend her life with, then doesn't recognize these very things with Dylan despite the neon sign planted beside him that consistently blinks "Soul Mate" at her. Their path to happiness is contrived and long-winded as the viewer begins to fantasize about knocking some sense into both of them. They're lovers. They're best friends. What is the problem?

As a whole, the film is unreliable, but not without its passing diversions. If the screenplay manages the wacky feat of meandering while feeling overstuffed and undernourished, some of the dialogue interplay is quick and rhythmic. The sex scenes, if a little demure nudity-wise, are far more incisive than those typically found in romantic comedies. There's a running joke involving Semisonic's "Closing Time" that pays off nicely at the end, a sly reference to "Easy A" heroine Olive Penderghast, and the section where Jamie accompanies Dylan to L.A. as he visits his family for the Fourth of July weekend is better than any of the Manhattan material. Jenna Elfman (2003's "Looney Tunes: Back in Action") and Nolan Gould (TV's "Modern Family") are memorably down-to-earth and unaffected as Dylan's loving sister Annie and nephew Sam, respectively, and unfailing character actor Richard Jenkins (2010's "Let Me In") makes the most of a clichéd type, that of a father mentally deteriorating from Alzheimer's. Director Will Gluck underlines this disease with a maudlin highlighter, however, and he isn't helped in his ill-advised use of some particularly bad, overacting extras who are always giving Mr. Harper's off-kilter behavior disapproving dirty looks. Also turning up, Patricia Clarkson (2010's "Cairo Time") cements her place as the go-to thespian for offbeat, loosey-goosey matriarchal figures as Jamie's mother Lorna; Woody Harrelson (2009's "Zombieland") is colorful, if poorly used, as Dylan's very much gay co-worker Tommy; and Emma Stone (such a standout in the aforementioned "Easy A") and Andy Samberg (2009's "I Love You, Man") breeze by in stereotypical cameos as Dylan's and Jamie's exes.

Early on in "Friends with Benefits," Jamie and Dylan watch a fictional romantic comedy starring Jason Segel and Rashida Jones filled with every last trite chestnut the genre is so often guilty of. Jamie pines for a relationship like the ones she sees in movies, and director Will Gluck ultimately abides by calling back to them in his own film. While some are used as winking comments on cinematic love stories, others just fall into the trap of threadbare convention. There's a pop song-laden soundtrack, a music score of rousing, manipulative strings, and a plot that must be drug out as misunderstandings and arguments arise and subsequent apologies and professions of love take over. Jamie and Dylan are stuck in the middle like marionettes on strings, going through the motions of a strained story that dumbs them down and doesn't even rile up much in the way of charisma between the two central actors. Mediocre more than an utter failure, "Friends with Benefits" ought to be forgotten in the shadow of the smarter, funnier, sweeter, and altogether superior "No Strings Attached." In that film, it felt like Kutcher and Portman were meant to be together. Here, Timberlake and Kunis connect only because the script requires that they do.