The late Nelson Mandela talked frequently of the two sides of being a prisoner, or as he so often said, a slave stuck in a jail.

He said there were emotions almost painfully in conflict with each other. One was the absolute destitute resignation and acceptance of your prison life. The other was the constant bubble of hope for freedom and a life which has been all but forgotten.

Rarely do you see that conflict more clearly expressed than in "A Midnight Cry," the James DeVita play that opened over the weekend at First Stage Children’s Theater.

The slogan of First Stage, and it is much more than just a slogan dreamed up by some marketing committee, is "Transforming Lives Through Theater."

This play is an example of just how important and powerful those words are to First Stage.

"A Midnight Cry" tells the story of Lida, a young slave in Missouri and her journey to freedom along the Underground Railroad which took her through Milwaukee on her way to Canada.

It’s an emotionally packed packed story, filled with all the horror of slavery, pain, being sold away from your family, whippings and desperate avoidance of the man with the gun and whip.

First Stage recommends this play only for children who are over 8 years old, and it’s because of those horrors.

When Lida, played with exquisite grace by Malkia Stampley, stands facing the audience which her bare back providing the target. We hold our breath in anticipation. And surely, Todd Denning, playing the white farm hand Jessup, uses a crack whip to create blistering sound in the space of the theater.

He is far enough back so there’s no danger that he will actually whip Stampley, but the way that whip cracks and her body cringes is enough to make an audience gasp and squirm in their seats in discomfort.

"My soul wants something new," Stampley sings after the whipping. She doesn’t know precisely what it is, but she knows that "people talk like freedom is like a city you can go to."

At the encouragement of her Uncle Eli, Lida leaves under the cover of night, headed for the Mississippi and the path to freedom. "Big River" sings the cast, a dual spiritual testament to both the power of the river and the goal that it has become for the runaway slave.

Musical Director Sheri Williams-Pannell weaves part of the spirituals through the production, capturing both the hope and religious determination of the slaves in search of this mythic freedom.

From the very start of this play, we see the progression of Lida toward freedom.  It begins with learning her numbers and learning to read and white. This play is about her journey.

There’s a strong cast at the Todd Wehr Theater and, led by Stampley, they tell a complicated story with marvelous simplicity and strength.

Matt Daniels, as the overseer who disciplines, punishes and eventually searches relentlessly for the escaped Lida, continues his string of superlative performances in Milwaukee. Since Daniels moved here from Chicago, he has established himself at the top of the acting pyramid.

Mark Corkins, who is the powerful owner of the slaves in the first act and the reverend who leads Lida to the escape path in the second, continues to dazzle. He just finished playing a horrific prison guard and slaughterer in "Burying the Bones" at In Tandem, and now has to channel the slave owner. His ability is crushingly good.

Gavin Lawrence as Eli is the symbol of achievement and improvement in the world of the slave. He brings humor, wisdom and a relentless drive to his role and provides the beacon of what kinds of hope await those who work for it.

Much of this play is dark and full of agony so parents should take care about whether their children can cope with the kinds of brutality they will see. But it is well worth a little discomfort to see the brilliance of this slice of our history.

"A Midnight Cry" runs through Feb. 9. Information is available at firststage.org.