Rudy Valdez’s The Sentence is the kind of film that’s going to make you cry. You’ll find yourself crying angry tears, sad tears, and, at times, even happy tears. But trust us, you’ll need to brace yourself for it. Audiences at Sundance probably felt the same way, giving Valdez the Sundance 2018 Audience Award: U.S. Documentary. Compiled from hundreds of hours worth of footage of his nieces, their father, and his own extended family, The Sentence tells the story of Valdez’s sister Cindy. Having been given a mandatory minimum sentence for a conspiracy charge connected to crimes committed by her now-deceased boyfriend, Cindy has been taken away from her young daughters. We get to see them go to recitals, speak tearfully with Cindy over the phone, and slowly grow before our eyes as their uncle begins what seems a futile effort to get Cindy out of prison.

Almost uncomfortably personal — we are watching home family videos, basically — this HBO documentary ends up giving a face to pressing issues of prison and criminal justice reform. In many ways, it offers a flip-side to the Orange is the New Black narrative, showing us what goes on in the households of those who have been locked away. “Missing my daughters grow up,” says Cindy at one point, “that’s what I was sentenced to.”

The doc, which was years in the making, is ultimately an attempt to give voice to the voiceless. “All my life I felt I didn’t have a voice,” he said while accepting the Sundance award earlier this year. “I felt like my community was underserved. I felt like my family was underserved. I kept waiting for somebody to help us. Somebody to step up to the plate. And when my sister was given a 15-year prison sentence for a first-time non-violent offense, six years after the fact, and I got that punch in the gut; I decided that I wasn’t going to wait for somebody to give me a voice.” He would be that voice. He would give his sister a voice. And she couldn’t have asked for a better platform than The Sentence.

The Sentence opens in select theaters on October 12 and premieres October 15, 2018 on HBO.