A well-written screen character doesn’t betray his motives early on. Thus, when itenerant handyman Noah (Marc Menchaca) offers to help the overwhelmed Diane (C.K. McFarland) with her son, Auggie (Tobias Segal), who has muscular dystrophy, it seems like simple, saintly compassion.

And speaking of saints, Diane is dealing with not just Auggie, but an ex-farmer husband  Bob (Ron Hayden) who appears to have Alzheimer’s and is prone to wandering. And then there’s embittered daughter Lainey (Frances Shaw), who smokes and drinks and sulks and is no help at all. Diane works at a supermarket, dragging Bob along to work to babysit him, leaving Auggie on his own with Lainey.

Until Noah shows up. He tries to connect with Auggie, “August,” whom he calls Gus. He puzzles over Lainey and laughs at Bob’s occasional, accident joke.

Everybody is trapped in Llano, Texas, trapped in lives of abject misery with nothing to look forward to in the bleaker-than-bleak “This is Where We Live.” Why Noah would inject himself into this situation is a mystery this film — co-written and co-directed by Menchaca and Josh Barrett — sets about telling us — eventually.

McFarland makes a moving Ma Joad figure in this drama, weeping when no one is watching her at work, fretting over the fact that her “boy” is no longer a boy, even if she takes offense at Noah’s efforts to take what he thinks Gus wants into consideration.

Her one break is that odd moment when her husband reminds her who he once was.

“There you are!”

Menchaca is properly cryptic as Noah, though his drunk scenes could use some work. Segal gives a lot of “cute” touches to Gus, who is written as a poet trapped in a barely functional body. Segal unfortunately never lets you forget there’s an “actor” inside this character’s infirmity.

It’s a downbeat “What’s Eating Gilbert Grape” without the laughs, with only the occasional sharp, sad observation about life and relationships.

“When you don’t feel, things kind of fall apart.”

But for all its sure-handed sense of place, its occasional grace notes of loss, grief and misery, “This is Where We Live” fails to seize and break our hearts, keeping its glum characters at arm’s length and doling out “hope” in tiny, cloying teaspoon-size servings.

Screenings: www.floridafilmfestival.com