“I wrote a paper for class where I tried to imagine my life as a soldier with you,” teenager Sadie (Sophia Mitri Schloss) writes in the most recent letter to her deployed father. “Mr. Lee will probably hate it. Teachers can’t handle violent stuff even if it’s literally everywhere.” As the newest trailer for Megan Griffiths’ film hints, Sadie’s preoccupation with “violent stuff” will eventually lead to real-life consequences.

Through the eyes of a 13-year-old girl, “Sadie” depicts the domestic struggles of deployment that military families experience as their loved ones are in constant danger overseas. Though Sadie remains completely devoted to her father, despite his weary false promises of return, her mother (Melanie Lynskey) is on the verge of giving up. When a new male presence (John Gallagher Jr.) threatens to break up her family, Sadie’s already-unsteady demeanor begins to take a worrisome route.

Lynskey’s recent credits include “Girl Boss,” “Togetherness,” and Netflix feature “I Don’t Feel at Home in this World Anymore.” She currently stars in Hulu’s anthology series “Castle Rock.”

Griffths has worked in television and features. Her directorial credits include episodes of “Animal Kingdom,” “Graves,” “Room 104,” and features “Lucky Them,” “The Night Stalker,” and “Eden.”

Prior to “Sadie’s” premiere at this year’s SXSW, Griffiths spoke with us about the increasing publicity around gender parity. “It’s well past time to challenge the power imbalance in our industry,” she said. “The world needs inclusivity right now. We need diverse stories and the empathy that those stories bring to our hearts, and we need it urgently.”

“Sadie,” which also features “Orange Is the New Black’s” Danielle Brooks, hits select theaters in New York and LA October 12.