“Barbara” opens Friday at Sundance Cinemas. PG-13, 1:45, three stars out of four.

It takes a while to get your bearings in Christopher Petzold’s “Barbara.” We know we’re in Germany by the language, but it’s not immediately apparent that the film is set in the early ’80s. And it takes even longer to realize that we’re on the wrong side of the Wall, in a backwater province of East Germany.

That sense of nervous dislocation that the viewer feels in the first few scenes — Where am I? Who is this person? Is she friend or foe? — efficently evokes the muted terror that its characters, especially the title character (Nina Foss) feels. It reminded me of “The Lives of Others,” except that in that film, the secret police are an ever-present, malevolent force. In “Barbara,” we hardly even see the police, but their unseen, watchful presence pervades the film.

Barbara is a doctor from Berlin who has been exiled to the province for some unspecified slight. Foss plays her as composed, almost aloof, but as the film goes on we see the terror lurking beneath that exterior. The police do eventually visit her, suddenly popping up, tearing up her apartment and subjecting her to invasive body searches.

But the real terror begins after they leave, when Barbara nervously looks for them around every corner, wonders if the person she’s chatting with at the hospital, especially the genial doctor Andre (Ronald Zehrfeld), is secretly an informant for the police. In one scene, Andre tells Barbara why he was demoted from Berlin to the provinces, a tragic tale of a medical error with disastrous consequences. Barbara’s response is not compassion, but suspicion that Andre is an informant and the story is a cover. She has either correctly perceived a threat, or pushed away the only person in the area to attempt to connect with her. She’ll never know which.

And, it turns out, Barbara has reason to worry. She’s saving up enough money to defect with her West German lover, and is frightened that her plan will be found out. But at the hospital, she can’t help but be concerned for her patients, including a teenage girl who nearly died from meningitis at a work camp, and a teenage boy who may have suffered brain damage in a suicide attempt.

“Barbara” is a drama made up of quiet moments and meaningful glances. But they start adding up, pushing Barbara towards a difficult moral decision. In a way, her path reminded me of Rick’s in “Casablanca,” whether to flee evil or stay and do whatever good, however small, within its borders. It’s a quiet film and, with its somewhat cryptic title, one that audiences could easily overlook. But try not to — there’s a lot going on beneath those still waters.