“Ida” opens Friday at Sundance Cinemas. PG-13, 1:20, three and a half stars out of four.

At first, Ida is barely there. Pawel Pawilkowski shoots the opening scenes of “Ida” with the characters at the bottom of the frame, a lot of empty space above them. Which is fitting, because they are nuns in a Polish convent; having renounced the earthly world, they are focused heavenward, on the world that awaits ththe eem.

Except that, for some of us, the earthly world is not so easy to forget.

One of those nuns at the bottom of the frame is Anna (Agata Trzebuchowska), who has been raised in the convent since she was an infant. Now 18, Anna is told by her Mother Superior that she should visit her one living relative before she takes her final vows. She goes to visit her Aunt Wanda (Agata Kulesza), a cynical and powerful judge in the new Communist Poland, and gets some shocking news. Anna’s real name is Ida. She’s Jewish. And her parents were killed by the Na

Together, Wanda and Ida travel to the family’s hometown in the countryside, asking questions about Ida’s parents and what happened to them. These are questions that the locals don’t want to be asked; “Oh, the Jews always kept to themselves,” people tell them, their nervous eyes betraying their polite ignorance. “Ida” is structured a little like a murder mystery, with a mismatched pair of sleuths — the innocent novitiate and the chain-smoking, worldly judge — circling closer and closer to the truth.

But, of course, “Ida” is much more than a mystery. It’s a story about powerful political forces that can obliterate individuals without a trace, and what happens to those who survive. Ida’s innocence mirrors the collective and willful ignorance of a nation, but perhaps she alone can face the truth because she has no culpability. Wanda, meanwhile, knows too much, having survived one totalitarian regime and become a well-compensated cog in another, grown brittle with self-loathing.

Devastatingly brisk at 80 minutes, “Ida” is a beautiful film to watch, with Pawilowski (“My Summer of Love”) using black-and-white cinematography to create stunningly composed scenes that have the weight of historical photographs and the urgency of real life. The film has a terrible beauty; when one character dies, it’s treated almost offhandedly, underscore how cheap life is in this world.

Kulesza is flinty-eyed, even funny at times, as Wanda, but the film belongs to the amazing newcomer Trzebuchowska, who gives Ida a quiet, watchful purposeness, as she sees first-hand all the awfulness of the world and decide whether the convent has become too limiting for her now, or a refuge.

In the last shot, Pawikowski shows us Ida again, but this time she’s not at the bottom of the frame. She’s exactly centered, walking purposefully forward into a future of her own choosing.