He proposes. She upchucks. Not a very auspicious start to a beautiful engagement. Indeed, the vomit is the beginning of the end for Doug (William Jackson Harper) and Lori (Aya Cash), but it's only just the beginning of "We Broke Up," a sweet, sad, little story of love lost, and transformed.

One would be tempted to call it a "rom-com," but the film is light on the romance, more poignant than funny. Unfortunately, we haven't yet come up with a pithy title for the subgenre of moving and melancholy movies about adults and their emotional baggage.

While rom-coms tend to be wordy, "We Broke Up" is more about the silence between these soon-to-be exes. Director Jeff Rosenberg (who co-wrote the script with Laura Jacqmin) makes good use of visual storytelling to highlight the irony afoot, which is that 12 hours after their 10-year relationship implodes in a parking lot, Doug and Lori have to hit the road for her sister's wedding.

Doug, as the "king of the ushers," insists on accompanying her, and somewhere along the way, they decide to hide the split. But the little white lie worms its way into every dark emotional crevice, threatening to upend every interpersonal relationship under the roof at Camp Arrowhead. It's a low-stakes conflict, but deeply felt.

Lori and Doug's awkward energy is instantly thrown into sharp relief by the bubbly bride, Bea (Sarah Bolger), and groom, Jayson (Tony Cavalero), who are like two human golden retrievers in love. Having met a month ago, their enthusiasm and fearlessness only highlight Lori's reservations and Doug's frustrations with said reservations.

Rosenberg fills out the rest of "We Broke Up" with your standard-issue whimsical indie comedy score and wacky supporting characters. The secret weapon, however, is Cavalero as Jayson. With an outsize presence that is a combination of Adam Devine and Seann William Scott, Cavalero steals the show. Jayson's the only character with any passion, and a clear, strong desire to achieve his goal of marrying Bea. He evolves from the weird future brother-in-law to become, honestly, inspiring.

Taking on a leading man role, Harper is tasked with carrying the heavier emotional weight, but he more than proves his charm and chops, even though he's left spinning his wheels a bit without enough material to work with. Though, as he enters a rustic cabin in this mostly white enclave, you may fight the urge to shout "get out!" as visions of his turn in 2019's folk horror flick "Midsommar" dance in your head.

Some of the zanier comedy moments don't quite match the energy and pacing of this film, which is far darker than it is funny, despite some of the scripted jokes. While "We Broke Up" is focused, lean and heartfelt, it does feel at times a bit insubstantial. It's missing the "why" at the center of this conflict, particularly with Lori, who remains an opaque character. But perhaps, in breakups, it's better if the "whys" are left unsaid.

We Broke Up

⋆⋆½ out of four stars

Rating: PG-13, language.

Theater: Oakdale; available on demand April 23.