Despite ticking off all the boxes of standard issue rom-com plotting, Jason Orley’s “I Want You Back” eventually twists itself into something much more complicated, frazzled, and ultimately less satisfying than the film’s log line would lead audiences to believe. Pulling liberally from other rom-coms before it — think of it as a spin on Griffin Dunne’s “Addicted to Love,” though less mean-spirited and with its own set of convoluted plot turns — “Love, Simon” screenwriters Isaac Aptaker and Elizabeth Berger’s latest retains the sweet center that drives the genre, but gets woefully lost in the details. What’s so complicated about making a good-natured romance with laughs to boot? Apparently, quite a bit.

Eighteen months into her relationship with nice guy personal trainer Noah (Scott Eastwood), and Emma is shocked to discover that he wants out. Noah has plans, you see, and Emma is so stuck in a rut that he can’t imagine a world in which he can move forward with her in tow. While Aptaker and Berger’s script eventually offers up reasons as to why Emma is still living a mostly post-college existence — “29 is the new 16!” she yells at Noah during their breakup, an unnerving observation on many accounts, the least of which being that she is actually 32 — they are too soon glossed over in hopes of getting the wacky train back on the tracks. Meanwhile, Peter’s girlfriend Anne (Gina Rodriguez) has similar reasons for breaking it off after six years: he’s just not growing or evolving, and Anne is itching to mix things up. Soon enough, both Noah and Anne have met new partners, while Emma and Peter are so heartbroken that they spend most of their workday sobbing in stairwells. Enter: a genuinely inspired meet-cute, as Emma and Peter actually work in the same building, and when they run into each other during one of their daily cry breaks, they can’t help but recognize the funny symmetry of their lives. What if, these newly minted “sadness sisters,” wonder, they could help the other one get back their recent exes? What could possibly go wrong?

Soon, Peter is heading off to Noah’s gym to take personal training classes (during which he will wildly pry into Noah’s personal life, in hopes of reminding him why Emma is so great and new girlfriend Ginny isn’t up to snuff), while Emma infiltrates school teacher Anne’s middle school production of “Little Shop of Horrors,” as directed by Anne’s new boyfriend Logan (Manny Jacinto). Yes, it’s convoluted and improbable — how Emma is getting all this time off her job to spend hanging around at a middle school is just one of many questions inspired by the film’s plot — but that’s the least of the film’s problems. Most damningly: Slate and Day are indeed charming together, but their romantic chemistry is lacking. Instead, they seem more like funny friends, BFFs in the making, delightful rascals who are never, ever gonna kiss (something Orley appears to, quite oddly, realize down to even the very last minute of the film). Perhaps that’s why “I Want You Back” tends to keep the duo apart, when it really should be slamming them together at every possible moment, in hopes of capitalizing on the power of the “slow burn” romance Emma chats about so much. It’s the old “such terrible food, and in such small portions” problem: Slate and Day don’t have the appropriate zip to be a cheer-for-them romantic couple, but we also rarely see them together enough to ever get invested in the possibility they could work out. Instead, we get scenes in which Peter is stuck in a hamper while Noah and Ginny (Clark Backo) go at it mere inches from his head, or a protracted subplot in which Emma bonds with a tough kiddo during her misbegotten after-school play stints (at least Emma’s bit eventually pays off, but damn if it feels squicky for far too long). There’s a drawn-out sequence in which Peter and Noah go out clubbing, only for the pair to end up at a high school party (well, kind of), all the better for “Big Time Adolescence” director Orley to bring out his former star Pete Davidson for an amusing, if wholly out of place cameo. It’s not romantic and it’s only funny in fits and starts, so what the heck kind of rom-com is “I Want You Back” anyway? There are some grace notes tucked in the film, like a desire to never cast anyone as a villain (not even Anne, who initially seems like a pill, or Ginny, who would be all too easy to turn into a man-stealing baddie) and finding ways for both Emma and Peter to explore other aspects of their lives in addition to their dashed romantic hopes. There’s a deeper, more serious film at the heart of “I Want You Back,” but a bent toward offering up off-kilter comedic set pieces instead keeps it from hitting any harder truths. Does that not sound funny, though, or romantic? Wrong: It sounds human and real and honest, all of the things that rom-coms can (and should) excel at. “I Want You Back” only briefly embraces them, before slipping back into bad old habits, the exact kind that should have been dumped long ago.

Grade: C+

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