Prison bars separate a 7-year-old and her dad

In “Xiara’s Song,” a poignant documentary airing at 7 p.m. on Father’s Day on Cinemax, the victim/heroine is a 7-year-old girl so bright and so sassy and so delightful that her circumstances, already dire, are doubly heart-rending.

Directed by Liz Garbus and co-produced by Garbus and Rory Kennedy, the daughter of Sen. Robert F. Kennedy, “Xiara’s” shows us the emotional damage done to children and families when parents are sent to prison.

With millions of children in America growing up with a parent behind bars, it is a subject worthy of discussion.

Xiara’s father is the rap-singing Henry, serving time for a gun conviction, his third stretch.

Xiara and Henry adore each other and sing original songs to each other, first in the visitors room at the Washington, D.C., jail and later over the phone when Henry is transferred to a federal prison 300 miles away.

In Xiara’s world, having fathers in jail is commonplace. “She’s going to cry,” she says of her girlfriend, “because her father went to jail too.”

The filmmakers gained access to the D.C. jail, and their portrayal of inmates and their suffocating, noisy, fear-inspiring surroundings is chilling. Home movies of Henry, Xiara and her mother, Aracelli, add to the ache.

Aracelli, understandably, is brimming with quiet anger at Henry, refusing to visit him and talking coldly to him when he calls. Henry is glib, manipulative and narcissistic.

Xiara is mad at her mother and prefers her father -- “He’s better, he’s cool, he is.” All the child counselors and psychologists in the world -- happily absent in “Xiara’s” -- could not have given a better description of a disintegrating family.

True, Garbus and Kennedy pull some punches. Viewers are left to guess at Henry’s full rap sheet and sentence. There’s a fleeting reference to 10 years, but it’s unclear.

Who were Henry’s victims? Do they have children who are suffering? Nothing wrong with having a sympathetic point of view, but some contrary facts might have strengthened the effort.

“Xiara’s Song” offers no solutions but it firmly pokes our collective conscience, a noble goal by anybody’s definition.