Rose Lorkowski (Amy Adams) and and her sister Emma (Emily Blunt) start a crime scene clean-up business in the black comedy Sunshine Cleaning. (E1 Films Media)

Isn't "quirky" supposed to be rare? A quirky film has that oddball, offbeat quality that separates the indie from the mainstream. It's the mark of the outsider, the individual, the boho-beatnik passport to cool.

Schematic to the bone and lighter than, well, sunshine, Sunshine Cleaning features excellent performances, even if the film isn't actually excellent itself.

But it's also a meaningless farce. Quirky movies have become so profitable in the past few years that there's a new one riding in from a Sundance workshop every month or so – a feel-good dramedy with dorks, à la Juno. The best are an antidote to the bloated comic-book fantasia of the multiplex, but the worst are as cynically formulaic as a Saw movie (Napoleon Dynamite), self-consciously parading that combo of quirk and heart (quearkt?) that producers pray will make millions.

Sunshine Cleaners contains a few hallmarks of this phenomenon, including Alan Arkin as a befuddled grandfather, a cute kid, an oddball job, sadness to overcome and that word in the title. Not clear enough for you? It's also "from the producers of Little Miss Sunshine."

What's troubling about the quirk blitz is that a decent little movie like Sunshine Cleaning risks being written off as an imposter. Schematic to the bone and lighter than, well, sunshine, it features excellent performances, even if it isn't actually excellent itself. Excellence is rarely the goal of a quirky movie, anyway – a warm, quickly forgotten glow is the best-case scenario. Sunshine Cleaning doesn't deviate: it's a gossamer drama where the sum is greater than its modest parts.

Amy Adams plays Rose, a woman who is losing touch with her happiness, requiring reminders in the form of self-help Post-it notes on her bathroom mirror: "You are strong!" With her red ponytail and nervous smile, she's still outwardly sunny, a variation on her high school cheerleader self, the girl who dated the quarterback.

But that was a good 15 years ago, and now Rose is cleaning houses and struggling to support her son, Oscar (Jason Spevack). She's still sleeping with the quarterback, an affable cop named Mac (Steve Zahn, a standby in any quirky movie) who actually married someone else. Their affair takes place in shabby hotels when Rose's sullen sister, Norah (Emily Blunt), looks after Oscar.

Norah, kohl-eyed and appealingly unfocused, is dealing (or not) with her own stasis. She keeps getting fired from jobs and lives at home with the family patriarch, Joe (Arkin). Joe's get-rich schemes – selling caramel popcorn and shrimp, thankfully not together – keep him at a distance from reality; he's the kindly grandpa with empty promises of Disneyland. These emotional cripples are all, it turns out, in an unacknowledged state of grief that has to do with the absence of the mother of the family.

From left, family members Oscar (Jason Spevack), Rose, Norah and father Joe (Alan Arkin) have a dysfunctional relationship in Sunshine Cleaning. (E1 Films Media)

What pulls the family out of its collective funk is a weird new job that involves not a broken-down VW bus but a broken-down van. At Mac's suggestion, Rose starts a business cleaning up after crime scenes. There's inherent comedy in seeing two pretty women scrubbing human waste out of a mattress with toothbrushes, even as it turns your stomach like a salad spinner. Rose has a knack for the work, it turns out, and as the pair grow expert at their "craft," a surprising sense of achievement overtakes them. They don't feel like losers anymore, and so they stop acting like losers. Norah makes overtures toward another lonely woman (the always winning Mary Lynn Rajskub, master of understatement), putting herself in the world for the first time. Blunt, playing American with ease, delivers a lovely, subtle performance; she never makes rebellious Norah stupid or crass, only hurt.

When Rose attends a baby shower filled with high school frenemies gleeful to pick apart her perceived failings, she fends them off by explaining, with great pride, that she runs "a business." Adams – such an exuberant actor – is radiant as she waxes poetic: "We come into people's lives when they have experienced something profound and sad, and we help." Well, mostly the job seems to be about containing airborne particles, but Adams brings true emotion to this small moment.

Small, of course, is the operative word. The only truths parsed in Sunshine Cleaning are tiny ones, which feels like a bit of a rip-off when it turns out that the director is Christine Jeffs (working from a script by Megan Holley), who made the underseen New Zealand coming-of-age film Rain and the ambitious Sylvia Plath biopic Sylvia. In both those films, Jeffs proved herself quietly attentive to the depths of loss and highly curious about the fractured female psyche. Sunshine Cleaning doesn't come close to the intensity Jeffs is capable of, but it repeats her signature respect for character.

It's too bad that Jeffs's gentle approach is limited by a script that's hell-bent on cute. I wanted the film to go further, to make more of Winston (Clifton Collins Jr.), the one-armed, mustachioed manager of a janitorial supplies store, a beacon of sanity and kindness. And I wanted more of Norah, who recedes abruptly. But despite these quibbles with quirk, I'm glad that Jeffs is out there, turning her gaze on women's stories in this bromantic age. It's unfortunate that this minor bout of feel-good feels far too obvious.

Sunshine Cleaning opens in Toronto, Montreal and Vancouver on March 27, with other Canadian cities to follow on April 3.

Katrina Onstad is the film columnist for CBCNews.ca.