Sophia, 5, climbs her backyard tree one last time, barefoot in a black flowered dress. Inside her house, boxes line the walls. She can barely make herself pack.

Her parents are getting divorced.

HBO’s new documentary, “Don’t Divorce Me,” strings together interviews with more than 20 kids ages 5 to 10. They’re spunky, articulate and heartbreaking as they flip through photo albums and narrate home movies.

There are bad divorces and worse divorces. Grace, 9, likes getting double Christmas and birthday presents, but there are far more stories of shouting and slammed doors in the middle of the night. One 7-year-old vehemently insists he’s over the split, then casually mentions his nightmares.

One montage features the children rattling off shared-custody schedules like multiplication tables. “Home for me is in a car,” laments one girl whose parents live more than 30 minutes apart.

Some of these kids still seem haunted, while others offer a ray of hope. A gregarious 8-year-old named Henry proudly introduces his 105-year-old great-grandmother and says he has “awesome parents.”

“Don’t Divorce Me” will be a giant guilt bomb for couples in the process of splitting, but at half an hour minus a few song montages, it’s a densely packed lesson on what will seem, for those not trapped in conflict, like common-sense guidelines.

For kids who have trouble talking about their feelings, it provides a spectrum of reactions to relate to. Maybe some mom and dads out there needs to hear their daughter say, “I feel like Sophia.”