If a picture is worth a thousand words, a cinéma vérité documentary is worth ten thousand. Such is the case with Mother’s Day, a heartbreaking observational film from Elizabeth Lo and R.J. Lozada, which follows groups of children as they travel long distances by bus to visit their mothers in prison on Mother’s Day. The documentary’s fly-on-the-wall approach conveys a depth of emotion that statistics and interviews with experts frequently cannot; observing these children, we become privy to the trauma of growing up without a present mother. We can begin to comprehend the steep price an entire generation of youth will pay for America’s high incarceration rate.

The charity organization Get on the Bus affords young Californians this opportunity to visit their mothers in remote, rural prisons that are often difficult to access for low-income families. The children, who range from babies to young adults, are among the more than five million kids in the United States who either have or have had an incarcerated parent. That number breaks down to one in 14 children; for black children, it’s one in nine.

“This is a much-overlooked part of the incarceration issue,” Lo told The Atlantic, “and that's why we wanted to make this film from the children's point of view.”

Lo shot the film over many overnight bus rides to two California prisons—the Folsom Women’s Facility and the California Institution for Women. “Sometimes, we would talk to all the families ahead of the weekend to find out who would be a compelling person to follow,” Lo said, “and sometimes we would just go with our instincts and discover who to film after we boarded the buses.” The journey to the prisons was sometimes as long as 10 hours. Often, Lo and her co-director filmed for 24 hours straight.

“It was fun, but it wasn’t fun,” 13-year-old Hezekiah says in the film after he returns from the bus trip. “There was nothing I could do about it, so you have to accept the fact that you have to leave again…I’m kinda getting used to the feeling of getting hurt.”