Though she has a penchant for surprises, Megan Griffiths finding a story in Shady Plains Mobile Home Park, where her latest “Sadie” is set, isn’t one of them. In a just world, Griffiths would likely be on her second or third studio dramas that makes noise around Oscar time for the unique ability to build a social consciousness into gripping entertainment, but given that those films only seem to be bestowed these days as favors to directors wanting a break between blockbusters, the filmmaker has consistently made films that are unusual in the indie world, as attuned to the plight of marginalized people and communities as she is to what’s compelling drama. “Sadie” is rich with possibility in both regards as it centers on the 13-year-old Sadie (Sophia Mitri Schloss) and her mother Rae (Melanie Lynskey).

When Griffiths finds them, the two are at odds over someone who isn’t there – Sadie’s father, who she dutifully writes to as he serves overseas in the military, receiving replies from time to time while her mother hasn’t received such correspondence in three years. While Sadie holds out hope her father will come home, Rae knows even if he does, a reunion is likely not in the cards, presumably parting well before he was deployed emotionally if not physically, and although she’s increasingly emboldened to dance less around the subject as she often has with Sadie, who has figured some things out for herself as she’s gotten older, it remains delicate. Still, the issue is forced with the arrival of Cyrus (John Gallagher Jr.), a former pilot-turned-mechanic who takes up residence in the mobile home park and immediately has eyes for Rae.

Things may move way too fast for Rae, who reluctantly gives in to Cyrus’ advances, and certainly for Sadie, who shows a flair for undermining those who threaten to get in the way of her family like the nebbishy Bradley (Tony Hale), who clearly also has feelings for Rae yet never acts on them. However, Griffiths finds just the right clip to turn the tension that’s built up between the three into a searing domestic thriller, filled with the revelation of Sadie and Rae have as they begin to recognize each other as individuals making their own decisions rather than mother and daughter with the drama resulting from when they assume too much about one another. One of the writer/director’s greatest gifts – showing empathy towards characters who don’t have much of it in their own lives by understanding their motives, as perverse as they may be in the case of her Richard Ramirez biography “The Night Stalker” or the abductors in the kidnapping thriller “Eden” – is on full display in “Sadie,” where Sadie and Rae are among many in Shady Plains who have few good options as a result of forces beyond their control and in struggling to make the best of a bad hand are bound to make a few choices they’d like to take back.

An impressive cast adds even more dimension to “Sadie,” as Schloss and Lynskey make the moments in which Sadie and Rae as compelling when they’re tentative, feeling each other out for clues on how they should act, as the times when they actually take action. The vibrancy of their performances is indicative of “Sadie” as a whole, with a supporting cast including Danielle Brooks as Rae’s confidant Carla and Tee Dennard as Sadie and Rae’s neighbor Deak that gives multiple meanings to the notion that tough lives build strong character, and production designer Ben Blankenship doing the quiet work of layering in history inside every location in the park, taking the expositional burden off the actors. (Working with editor Celia Beasley, Griffiths’ general narrative economy makes “Sadie” as sharp as a knife.) The past is also echoed and often electrified in an evocative score from Mike McCready, in a rare foray into film composing for the Pearl Jam guitarist, giving sonic shape to memories that continue to block Sadie and Rae when no one else can see them.

Of course in the larger picture, Sadie, Rae and the other denizens of Shady Plains are invisible in their own way, too, and by once again venturing into a place that few too other filmmakers are willing to look, Griffiths delivers a drama that crackles with a sense of discovery, not only for the characters onscreen in picking up the nuances of the complex relationship between a mother and daughter readjusting their perspective on one another as they enter a new age in a variety of different directions, but for audiences who so rarely see people who could so easily be their neighbors given the dignity of having their stories told onscreen. It’s the twist that brings “Sadie” so close to home that may be the most radical and thrilling of them all.

“Sadie” opens on October 12th. A full schedule of theaters and dates is here.