Walter Salles’ 1998 international breakthrough, Central Station, earned an Oscar nomination for the magnificent Fernanda Montenegro. Now in her 90s, the actress turns up toward the end of the director’s first feature in his native Brazil in 16 years, the shattering I’m Still Here (Ainda Estou Aqui), in a role that requires her to speak only through her expressive eyes. What makes the connection even more poignant is that she appears as the elderly, infirm version of the protagonist — a woman of quiet strength and resistance played by Montenegro’s daughter, Fernanda Torres, with extraordinary grace and dignity in the face of emotional suffering.

Many powerful films have been made about the 21 years of military dictatorship in Brazil, from 1964 through 1985, just as they have about similar oppressive regimes in neighboring South American countries like Chile, Argentina and Uruguay. The human rights abuses of systematic torture, murder and forced disappearances represent an open wound on the psyches of those nations, for which cinema has often served as a vessel for collective memory.

It’s not often, however, that the spirit of protest against the horrors of junta rule is viewed through such an intimate lens as I’m Still Here. That aspect is deepened by evidence throughout the film of Salles’ personal investment in the true story of the Paiva family after patriarch Rubens (Selton Mello), a former congressman, was taken from his Rio de Janeiro house in 1971, ostensibly to give a deposition, and never seen or heard from again.

Salles met the family in the late 1960s and spent a significant part of his youth in their home, which he credits as foundational to his cultural and political development. That accounts for the coursing vitality of the early scenes, as the five Paiva siblings dash back and forth between the house and the beach, and an extended family of friends of all ages seems to be constantly dropping by for drinks and meals and music and lively conversation.

There are sweet throwaway moments like two of the sisters dancing and singing along to the Serge Gainsbourg-Jane Birkin wispy make-out classic “Je t’aime … moi non plus,” without understanding the words. Just watching how one of the youngest kids, Marcelo (Guilherme Silveira), sweet-talks his way into keeping a stray dog they found on the beach conveys the warmth, spontaneity and affectionate scrappiness of the Paiva household dynamic. The young actors playing the kids are all disarmingly natural and appealing.

The first blunt intrusion into the family’s bubble of closeness and comfort comes when eldest daughter Vera (Valentina Herszage) is out with a group of friends and their car is pulled over at a tunnel roadblock. It’s a disturbing scene in which we see teenagers — just minutes earlier cruising along, sharing a joint and laughing — ordered at gunpoint to stand against a wall while military officers question them, searching their faces for any resemblance to the “terrorist killers” they’re looking to apprehend.

An occasional hushed phone conversation or private exchange with a friend suggests Rubens’ involvement in something that needs to be kept quiet. But the script by Murilo Hauser and Heitor Lorega, based on the book by Marcelo Rubens Paiva, saves those details until long after Rubens is taken into custody. That puts us in the same position as his wife and children, wondering what their father could possibly have done to put him in the regime’s crosshairs.

The chill of uncertainty is hardest on Rubens’ wife Eunice (Torres), who does what she can to hide what’s going on from the youngest kids. But having armed strangers in their house and a car parked across the street to keep a constant eye on them is tough to explain, and the older siblings are aware something is very wrong.

The situation escalates when Eunice is hauled off for interrogation. With Vera away in London with family friends, the next oldest, 15-year-old Eliana (Luiza Kozovski), is forced to accompany her mother, with bags put over their heads to keep them from knowing where they are being taken.

The interrogation scenes, set in a grim building with confinement cells, are harrowing. Eunice is sequestered for 12 days. Denied contact with the family lawyer, she’s kept completely in the dark about what’s happening to her daughter and is unable to learn where her husband is being held. She’s coerced over and over to identify people in photo files as possible insurgents, but aside from her husband, she recognizes only one woman who teaches at her daughter’s school. Her isolation and fear are made worse by the constant screams of people being tortured coming through the walls.

There are many moments of raw tenderness after Eunice is released — notably when one of her daughters watches from the bathroom doorway, face a mix of sorrow and terror, as her mother showers away 12 days of grime.

With the government refusing to acknowledge even that her husband was arrested, Eunice continues fishing for information, talking to Rubens’ friends who tell her the military is “shooting blind,” going after random people based on almost nothing concrete. Unable to make bank withdrawals without her husband’s signature, she struggles to keep up with expenses. At the same time, she begins studying the family lawyer’s case file, foreshadowing her eventual decision to relocate with the five children to São Paulo and return to college.

The chief focus of Marcelo Rubens Paiva’s book is essentially his mother’s quiet heroism — first as she single-handedly shoulders the responsibility of keeping the family together and protected, concealing her grief when the inevitable is confirmed, and subsequently when she earns a law degree at 48 and becomes active in a number of causes. That includes pushing for full acknowledgment from authorities of disappeared people like Rubens after democracy is returned to the country.

Salles’ heartfelt film jumps forward 25 years and then by almost 20 more, allowing us to absorb Eunice’s self-reinvention not in big crusading speeches but simply in her dedication to the work of keeping memories alive and not letting the abuses of the past be swept away.

Perhaps the most beautifully observed arc of the film is the gradual rebuilding of the family. As the children grow up and marry and grandchildren come along, they transition back into a noisy, joyful clan much like the one depicted in carefree scenes at the start. Even the simple process of sorting through boxes of family photos is viewed as a loving act of reclamation in a final stretch that will have many audiences in tears.

Torres (one of the stars of Salles’ terrific early film, Foreign Land, co-directed with Daniela Thomas) is a model of eloquent restraint, showing Eunice’s private pain and her necessary fortitude by the subtlest of means. Only once during the film does she raise her voice in anger after a sad occurrence, beating on the windows of the parked car watching the house in Rio and screaming at the two stone-faced men inside.

The final scenes in which Montenegro steps into the role are bittersweet, as Eunice has become nonverbal and uses a wheelchair, in steep decline with Alzheimer’s. The poignancy is almost overwhelming as we watch her gently lean in, her eyes lighting up and a hint of a smile forming, when Rubens’ photograph appears in a television program on the heroes of the resistance.

The movie looks gorgeous. Adrian Teijido’s agile cinematography uses 35mm to great grainy effect to evoke the ‘70s and Super 8mm home movies shot during that decade provide lovely punctuation. The other key asset to the film is Warren Ellis’ score, which starts out pensive and quietly troubling before shifting almost imperceptibly into a much more emotional vein with the surge of feeling that accompanies the forward time jumps.

While it could use a less generic international title that’s not also a well-known Stephen Sondheim song, I’m Still Here is a gripping, profoundly touching film with a deep well of pathos. It’s one of Salles’ best.