“I’ll never play music again,” a morose and mourning Zach (Dane DeHaan) sullenly declares after the death of his beloved girlfriend Beth (Aubrey Plaza), as if such a vow will bring her back or at least ease the pain of such a tragedy. Zach’s vow, much like the Jeff Baena film it appears in, “Life After Beth,” is funny and sweet and more than a bit misguided. Baena’s directorial debut (he previously penned “I Heart Huckabees,” so that should provide some insight into his brand of humor) centers on, well, life after Beth, as Zach and her family try to move on after the unexpected death of the apparently charming Beth, lost to a stray snake bite and forever gone.

Except she’s not forever gone, and Baena’s film attempts to steer the zombie genre into much more amusing and much more charming territory than we typically expect from films about the dead walking (call it a zom-rom-com, compare it to “Warm Bodies,” as all those things apply here). Zach isn’t just upset that Beth is dead, he’s upset about all the things he never told her, every word unsaid, the unfinished nature of their relationship (and life) itself. Zach’s grief morphs into predictably strange behavior – he begins wearing a colorful scarf of hers over his all-black uniform, he cooks up some Jello for her parents after hearing how much she loved it a child, he essentially stalks her family for a little shared mourning – and DeHaan appropriately infuses his darkly funny performance with the right kind of laughs.

Beth, of course, is not dead (this is a zombie movie, after all), and when she returns home to her stunned parents (John C. Reilly and Molly Shannon), the pair attempts to keep her away from Zach. Still fixated on his dead girlfriend, Zach discovers the rouse soon enough, and “Life After Beth” finally gets down to exploring its central question – what would you do if the person you love the most became a zombie? When it comes to Zach, the answer is to just use it as a second chance to do romance right, even if that means consistently checking to make sure your ever-worse-looking lady doesn’t want to eat your brains.

Baena imagines the transition from human to zombie in creative ways, with Beth’s vague confusion eventually giving in to literally blind rage, a desire to sleep in the attic amongst piles of insulation, and a burning desire to not let Zach leave her side.

Plaza is fully committed to her role, and as Beth becomes less and less outwardly human, Plaza both hams it up and finds the smidges of humanity that still continue to linger inside her character. Baena’s writing, however, doesn’t explore Beth nearly enough, and she exists as a sieve for Zach’s emotions and intentions, even as Plaza makes her feel more robust than she’s actually written. DeHaan similarly elevates the thinly written Zach, transforming him from a mealy-mouthed whiner into someone who at least approaches likable character territory. Still, the sense that Zach feels that Beth has been resurrected just for him to newly cherish is bothersome, and it encumbers the film from feeling real emotion.

The film eventually expands outwards to encompass a large zombie apocalypse, and that’s when its limited charms are lost nearly for good, as other people in Zach’s life begin to rise from the dead as Beth grows ever more monstrous. The result is something messy and muddled, a plot movement that takes away from the (kind of) beating heart of “Life After Beth.” Early on in the film, a distraught Zach is temporarily confused by a single figure – a man in a suit – running from something in the middle of the night. The man is obviously terrified, and it’s a nifty little device to show that something much larger is going on, and it’s about as big as Baena’s film should have gone when it comes to the outside apocalypse. Instead, Baena takes a well-tread road, leaving behind the guts of his promising story and never capitalizing on the charms of either romance or his leading lady.

SCORE: 6.1 / 10

"Life After Beth" will be distributed by A24 Films & DirectTV later this year.