PARK CITY, Utah — Dan Reynolds is a rock star, the lead singer of Imagine Dragons. He also grew up Mormon, and still considers himself a member of the church. It’s just that he wants to change it.

Believer, the new documentary that premiered at the Sundance Film Festival, tracks Reynolds’ crusade to use the platinum position he’s afforded as frontman of one of the most successful music acts in the world to confront the Church of the Latter-day Saints’ positions on the LGBTQ community and same-sex marriage, as well its treatment of its own members who identify as queer.

LDS policies on the LGBTQ community are notorious—and extremely punishing. Members who experience “same-sex attraction” are encouraged—commanded, really—to suppress their feelings, marry members of the opposite sex anyway, or, if they choose to continue to identify as gay or bisexual, abstain from sex.

Infamously, the Mormon Church was instrumental in the 2008 passing of Proposition 8 in California, which outlawed same-sex marriage, pressuring church members to give as much time and money as possible to campaign in support of their faith’s core beliefs.

The result of all this is a skyrocketing youth and teen suicide rate in Utah, the hub of the Mormon Church, where suicide cases are multiplying in numbers outpacing the rest of the nation. It’s too difficult to prove statistically, but not hard to imply: Closeted or tortured gay Mormon teens are likely a major factor in this alarming rise.

“This is an issue that needs to be talked about now,” Reynolds says in the film. “I don’t feel a need to denounce Mormonism. I do feel a need as a Mormon to take a stand against things that are hurting people.”

Believer chronicles roughly a year in that oft-emotional stand, culminating ecstatically in the LoveLoud music festival Reynolds staged this past summer in Utah. The goal of the festival was to unite members of the church with LGBTQ members of the community, LDS or otherwise, in a conversation about—and celebration of—love of all kinds, and acceptance regardless of religion or sexuality.

“ His awakening, that if he stayed silent about the church’s policies he is ‘standing then for bigotry,’ was accelerated when his friend, Neon Trees lead singer Tyler Glenn, came out of the closet. ”

Along the way, we meet members of the church who have been excommunicated because of their support of the LGBTQ community, families of children who committed suicide, and church members who have gone through the tortured experience of choosing to come out and grapple with what that means for their faith and their relationship with their families.

Believer may not break the mold when it comes to documentary filmmaking. If anything, there are more than a few notes of self-congratulation with the continued focus on Reynolds, a straight, married rock star. As much as the film is about an important mission, it’s about him on this mission, though that also lends the whole journey a vital, personal urgency.

Still, Believer, especially when it turns the camera to the LGBTQ members and their families, packs quite the powerful punch. How could it not, given the subject matter and these stakes? Stakes, after all, don’t come much bigger: religion vs. humanity, love, people’s lives. It feels like something big.

I don’t know much about Imagine Dragons, other than it’s apparently cool to scoff at their music. But, I mean, I run a little faster when a song of theirs comes on during a workout, sing along to the choruses that I somehow know every world to even though I’ve never actually sought out an Imagine Dragons song, and cried when “It’s Time” first played in the Perks of Being a Wallflower trailer. Seems to me their music may actually just be kind of easily appealing, and maybe even a bit inspiring?

Similarly, I didn’t know much about Dan Reynolds. I wasn’t aware that he was Mormon, and certainly wasn’t aware that he was a Mormon seeking to reform the church’s stance on LGBTQ rights and acceptance. It’s understandably a surprise to think about a Mormon rock star.

“I can’t think of more opposite worlds than that of a Mormon missionary, and that of a rock star,” Reynolds says.

Reynolds credits his time as a teenage Mormon missionary as one of the most formative experiences of his life, knocking on 100 doors before one person invites him in, yet unflappable due to the intensity of his devotion to the gospel he was spreading.

When we meet the singer, we’re also introduced to his wife, singer-songwriter Aja Volkman, and their three daughters. Their meet-cute, however, was, to border on hyperbolic terminology, forbidden. She wasn’t a church member, but took conversion classes before they got married. Her two best friends, a lesbian couple, refused to attend their wedding.

Reynolds is candid about the moral evolution he experienced after this. For most of his life, he felt uneasy about the church’s position on same-sex relationships but suppressed those misgivings because they didn’t affect him directly—something he posits that many Christians do.

His awakening, that if he stayed silent about the church’s policies he is “standing then for bigotry,” was accelerated when his friend, Neon Trees lead singer Tyler Glenn, came out of the closet. Glenn is also Mormon. He and Reynolds knew each other from their missionary days.

Glenn generously and openly talks about his experience grappling with his sexuality and suicidal thoughts as a closeted member of the church. He does a moving and clarifying job explaining why a gay person’s answer to the LDS policies isn’t as simple as just leaving. Extricating yourself from a belief system that has defined you and your relationships for your entire life is often not an option.

In fact, one wonders if Glenn might have been an interesting documentary subject in his own right. His recurrence in Believer does more than just wring its fair share of tears out of the audience. He’s a valuable and intimate human entry into a debate that, when framed in terms as dramatic and intense as “the Mormon war against the gay community,” is necessary.

Just as necessary is the presence of a little girl named Savannah, her hair tamed by a rainbow headband and beaming through her braces. Sitting next to her mother at a community center for LGBTQ Mormon youth, she explains what happened when she came out through testimony at church.

“He didn’t mess up when he gave me freckles, and he didn’t when he made me gay,” she told her fellow church members before, later in her speech when she used the word “lesbian,” her microphone was cut off. Savannah’s story shatters your heart, but her resilience pieces it right back together again, injecting more passion into her and Reynolds’ fight.

The parents of a teen boy named Stockton, who took his own life after coming out of the closet, are also interviewed. We see through them the paradox that Reynolds is motivated by: a family who loves and accepts their son, but a church that condemns him—and has too much blood on its hands because of it.

These are a few of the faces we meet that end up populating the crowd of 20,000 who attend the LoveLoud festival that Reynolds gets off the ground after tirelessly scaling every wall, each one more impossible than the one before it, in order to pull it off. The state of Utah very clearly didn’t want this festival. (Watching this film in Park City, an Uber ride away from the Salt Lake Temple, is a particularly electric experience.)

The concert is a rousing finale. It’s particularly tough to telegraph on film the energy and catharsis from a collective live experience like that, but Believer does an impeccable job of it. Similarly, there’s a crucial suggestion that the successful staging of the festival isn’t a finish line, but just the beginning of a movement to come.

“A determined Mormon is a scary thing,” Reynolds quips near the end of the film, riffing on a missionary’s knock-on-your-door gumption to encompass his ambition to not only stage a rock concert, but modernize an entire sect’s doctrine.

For all the talk of the Mormons waging a war on the LGBTQ community, and Reynolds retaliating with his own war against the church, what Believer makes clear is that the endgame here isn’t to battle, but rather broker a peace treaty. Metaphorically speaking, it’s the same goal: to stop the loss of life.