There’s a great subject and story at the heart of “Rebel Hearts,” a documentary about a group of feminist nuns who banded together to become a serious thorn in the side of the patriarchal Catholic Church. These women are unsung heroes of religious history when it comes to their role in breaking down barriers, and their contributions to women’s rights are to be applauded.

During the 1960s, the progressive nuns at the Immaculate Heart in Hollywood ran a women’s college that fostered independent thought and social activism. Some of the sisters marched with Martin Luther King Jr., and others created vibrant art with thinly-veiled criticisms of their religion and its leaders. It didn’t take long for the Catholic Church to see these women as a threat, accusing them of trying to undermine their authority. But these brave nuns stuck with their determination to chuck traditional, restrictive religious rules out the window and make a better world for Catholic women everywhere.

Pedro Kos‘s documentary is a rousing portrait of women who strived for autonomy in a world where powerful men wanted to control most aspects of their daily lives, from the type of clothing they wore to where and with whom they prayed. Eventually, over 300 nuns out of the 400 at Immaculate Heart opted to break off from the church, discovering that the new road ahead would be challenging but rewarding because they would face it together.

“Rebel Hearts” is an interesting story about these women who, at a time when females were expected to be subservient and quiet, dared to fight injustice and stand up for what’s right.