I wasn’t sure how I’d react to “The Zookeeper’s Wife.” Do we need yet another Holocaust film, I wondered. Did the film’s producers adapt another story about the murder of Jews for their own profit?

But this is a film about individual heroism, about people who risked everything in order to battle evil and save lives, about light in the midst of darkness. In the film, some Jewish lives are lost and many are saved. It is a saga that was not well known until the writer Diane Ackerman discovered a diary that would become the basis for her book and the source material for this film.

In the 1930s, Warsaw was a center of Jewish life, home to more than 350,000 Jews, who made up about 30 percent of the city’s total population. It also was home to one of Europe’s finest zoos; Dr. Jan Zabinski was highly regarded not only for the zoo he oversaw, but for the popular books about biology and animal behavior that he wrote. Working by his side, his wife, Antonina, an author of children’s books about animals, helped to care for the animals and run the zoo.

When Poland was invaded by Nazi Germany in 1939, the zoo suffered extensive damage and was forced to close. Many of its animals were killed in the bombings. The Zabinskis soon realized that their zoo grounds now could provide refuge for another species in danger of extinction — their Jewish friends and neighbors. What took place at the zoo during the war years provides the framework for what is an incredible story of two heroes, Righteous Among the Nations, who risked everything to save Jewish lives.

The visual contrast between a zoo that kept animals barred inside and a ghetto, just down the road, where Jews were kept behind barbed wire and walls, is powerful. Director Niki Caro and her crew worked extremely hard to create a world where both animals and human beings are confined for the amusement of others.

Both people and animals were in an alien environment — the only difference was that at least at first the animals were well cared for, while the Jews simply were being held for the slaughter.

Caro uses the cages in the zoo and in the ghetto to make her point. When the Nazis arrive, they seem to have the same disregard for some of the animals, shooting them at will, as they do with Jews. Though we see suffering on the streets of the ghetto, and eventually we see its destruction, we also see the incredible impact that a few good people could have. It was those same cages that once held their animals that the Zabinskis would use for Jews’ escape route. Director Caro and her cinematographer, Andrij Parekh, masterfully shot through those cages into dark places and shadowed hallways. That was the pathway to salvation.

Unlike in the ghetto, where confinement was a prelude to deportation and death, the zoos’ underground cages provided safety and comfort.

Jessica Chastain gives Antonina a strong presence. We watch Antonina’s character develop as she moves from the periphery, as a wife whose job is to assist her husband, into a woman who shows immense courage and takes control. She becomes the overseer of the safe haven and the engineer of the underground escape route. We watch her develop as a woman and as a human being, even as she takes greater and greater risks and the danger surrounding her intensifies. Chastain does a masterful job in the role.

Johan Hardenbergh provides a compelling portrayal of Antonina’s husband, Jan. The Flemish actor is soft and sensitive when the role calls for it, but at other times he is forceful and dynamic as the non-Jew who grew up with Jews and would not accept bias and hatred. In moving scenes, Zabinski twice goes to Dr. Jan Korczak (Arnost Goldflam), the famous author and orphanage director, and offers him an opportunity to escape to freedom. The second time, Korczak explains that he cannot leave his children. Instead, he asks the zoologist to help him put the children onto the freight train headed for the death camps. He does not want them to panic. Niki Caro’s direction of this scene is incredibly powerful. Every time that yet another child is lifted onto the death train another wound is inflicted on the viewer.

Daniel Bruhl does a fine job as the predatory Nazi Lutz Heck, and Israeli actors Efrat Dor and Iddo Goldberg, as Jews sheltered and saved by the Zabinskis, give moving and real portrayals. Tel Aviv native Shira Haas as the young Urszula, who leaves the ghetto psychologically damaged but comes alive on Passover eve to initiate a seder in hiding, deserves special mention. Harry Gregson-Williams’s musical score is superb.

How can a film set during the Holocaust be a feel-good movie, especially for Jews? Don’t get me wrong! I sat on the edge of my seat for a great deal of the movie. I worried about the growing power that Heck held over Antonina. As the Nazi in charge, what would he do?

Niki Caro does a fine job in navigating the screenplay, by Angela Workman, from suspense to pathos. In an odd touch, as the war comes to an end, little Jewish stars are painted on the walls of the zoo. When I asked Caro why she did that, she said that she just wanted to “honor those who had passed through the zoo, and that seemed like a lyrical and appropriate way to do it.”

This film honors not only those who survived, but those who sacrificed much and risked all to save Jewish lives. It is a film that must be seen.

Next week, Eric Goldman interviews Jessica Chastain and Niki Caro.