It could have gone so wrong. The premise of Christine Jeffs’ “Sunshine Cleaning” — down-on-their-luck siblings start a business cleaning houses after people have died in them — is ripe for the kind of quirk overload that sinks many an indie darling. But unlike “Little Miss Sunshine,” which was undone by its wacky cynicism, or “Juno,” with its fast-talking and unbelievable teens, this indie dramedy keeps itself grounded in the real world, and it turns out to be an empathetic and humorous portrayal of a struggling family. It’s a movie that sneaks up on you, and when it’s done, you’re slightly gobsmacked that it’s hit you so hard.

It helps to have Amy Adams in the lead role of Rose Lorkowski. Adams has a warmth and a vulnerability that make us latch onto her right away, and she uses every bit of that asset here. Rose is a woman in trouble when she decides to start the Sunshine Cleaning company with her sister Nora (Emily Blunt). Looming over Rose’s head are her adorable but overwhelming son, her mounting debt and her scheme-happy kook of a father (Alan Arkin). Facing such challenges, Adams creates an affecting portrait of working-class grit.

A warning: get ready to cry. A lot. “Sunshine Cleaning” should really be characterized as a tearjerker with a comedy at its center. Rose’s job gives the film a unique and rather profound way to think about loss. True, I’m a sucker for death — there’s no easier way to get me going — but the smart script and open-hearted performances make “Sunshine Cleaning” sentimental in the best way. This is a movie with a pure kind of love for its characters, wounded by time and grief. By the film’s end, Rose and her family have transitioned from crushed pain to something more hopeful.

The one problem with “Sunshine Cleaning” is that it ends far too abruptly, as if Jeffs decided to randomly pack it in one morning. The result is a conclusion that strives for open-ended and tantalizing ambiguity, but just winds up being frustrating. Beyond that, the film is a refreshing and soulful delight.

One last thing. It’s lovely to watch a movie that passes my mother’s test for whether or not a film cares about women: Is there a scene with two women just talking to each other? The fact that this is noteworthy is an unfortunate indictment of our current film landscape.