Some movies come to you, passing on their insights directly, underlining their message and themes. More challenging films make you come to them.

Morissa Maltz’s “The Unknown Country” is a rare example of the latter made even rarer by the fact that it’s a docu-drama.

Real people narrate anecdotes, truths about their lives as a waitress, a motel operator or a Texas dance hall owner, as our protagonist makes her way across the vast middle of America, from Minneapolis to South Dakota’s Pine Ridge Indian Reservation to Dallas and Big Bend, Texas.

Something, some trauma, put Tana (Lily Gladstone, star of the upcoming Scorsese epic “Killers of the Flower Moon”) on the road in a thirty year-old Cadillac DeVille, cracked windshield and ever-present cigarette, a sad woman with a story to tell that she’s not telling.

“You never know what’s going on in somebody’s life,” real-life waitress Pam Richter tells us, which is why she practically gushes over every single customer she serves, including Tana.

Tana was living in Minneapolis, we gather. She’s “just kinda floating” down the Blue Highways, convenience store to diner to motel, when she checks in with a relative, and next thing you know, she’s heading for a wedding.

She mixes with the happy couple (Lainey Bearkiller Shangreaux and Devin Shangreaux), plays with their daughter and the kids of others gathering for the nuptials. And she chats with acquaintances and relatives she hasn’t seen since she was a child. Everybody wants to know if she’s “been to the Rez,” Pine Ridge (also the setting of the colorful “War Pony”) and “How long are you gonna be here?”

Not long, of course. Just a taste of her past and a few folks gently boosting her sense of who she is thatnks to her heritage. But it’s not like she’s going back to where she started, Minneapolis, her home since she was eight years old. That ancient Caddy gives a hint of why she was there and who must’ve owned it before her.

Tana faces a traffic stop and a nervous, wordless moment of fear with a creeper at a remote gas station, but mostly just a lot of encounters with just folks — most of them perfectly nice, and much better company than the soundtrack of NPR stations and reactionary red state talk radio.

We get a better handle on Tana when she finally reaches a city. She’s a Native American woman whose “tribe” — people her own age, people who go out to honky tonks and dance halls — are outsiders who understand something of her outsider heritage.

The most direct comparison this film invites is to William Least Heat Moon’s best-selling road trip memoir of self-discovery, about the world he encountered off the interstates and along the aforementioned “Blue Highways.”

Tana’s trauma — a recent loss and the older dislocation from her home, perhaps with good cause — is internalized and not something she speaks about. Her “road trip” has a purpose, which we can guess once we get a handle on her destination. But her interior life is mostly just that as she takes in the family lives she grew up apart from and the family she’s never made for herself.

Gladstone carries the picture as a reactor — to the stories she hears from this waitress, that grandfatherly distant relative, the bride-to-be. But even those reactions are subdued.

“The Unknown Country” avoids melodrama and some obvious turns the story could take, but doesn’t. Truth be told, it could use more incidents, more drama, more insights into Tana’s journey, what she’s escaping and what she’s looking for.

It’s still a sweet, meditative drive through the flatlands across America’s middle, snowy north to line-dancing south.

Rating: unrated, smoking

Cast: Lily Gladstone, Lainey Bearkiller Shangreaux, Richard Ray Whitman, Devin Shangreaux, Pam Richter and Raymond Lee

Credits: Directed by Morissa Maltz, scripted by Morrisa Maltz, Lily Gladstone and Lainey Bearkiller Shangreaux. A Music Box release.

Running time: 1:25