Harriet Tubman was born a slave named Araminta “Minty” Ross in Maryland. She suffered all the usual indignities and violence inflicted upon slaves, but one injury in particular left her with permanent brain damage, which gave her, as she described “premonitions from God.”

According to a legal will, she was supposed to have been freed long ago, but when she eventually went to plead with her owner, it wasn’t for her own freedom but that of her unborn child. She had married a freeman who visited her frequently, but he didn’t want to have a baby who would be born a slave, and I suppose you can guess how her masters answered her.

So that’s when Harriet got it in her head to run away. I mean, it must have been in every slave’s head every day of their lives, but finding the courage and the opportunity to do it was prohibitive. Runaways were brought back and tortured before being put to death, to set an example for others. It would have been a powerful motivator for staying put, to say nothing of having to leave behind your loved ones. Of course, when your loved ones can be sold away without notice, it is perhaps not such a big risk after all.

At any rate, Harriet did leave one night, alone. She traveled to Philadelphia on foot, 145km, evading slave catchers and bounty hunters, hiding by day, guided by the north star at night. Eventually she made it to freedom: she survived.

In the film, Harriet (Cynthia Erivo) arrives in Philadelphia and meets William Still (Leslie Odom Jr.), a member of the Pennsylvania Anti-Slavery Society and conductor on the Underground Railroad. He is a meticulous record-keeper and Harriet’s is but one of many, many entries in his logbook. She then meets Marie (Janelle Monae), a black woman born free, who owns the rooming house where Harriet lives. Marie teaches Harriet a different kind of life. Of course, posing as a free woman is an improvement, but not exactly without risks or complications. People are still looking for her. Harriet could spend her whole life looking over her shoulder. But she doesn’t.

Instead, Harriet chooses not only to look back, but to go back. To rescue family, friends, and in fact dozens if not hundreds of strangers. To go back for others, and free them as well. If it’s hard enough to understand how someone could endure so much pain and torment, and then find the courage to escape, it’s darn near impossible to picture the kind of person who would risk it all to go back. But she does.

In fact, she went back 13 times over a period of 11 years, though each trip only put her more at risk. She became an esteemed conductor on the Underground Railroad, never having lost a soul on her midnight runs. Every successful conductor had a network of friends and allies, and though some were white abolitionists whose participation was a great risk, there were also many black people along her route who risked much more but did it anyway.

It’s about time someone put Harriet Tubman up on the big screen for all to admire, and director Kasi Lemmons seems to understand the weight of her responsibility. The incredible thing is, she chooses to do it without the usual trappings of the slave film. Of course, those are largely understood by now, and their threat is still heavily felt. Instead Lemmons focuses on Harriet’s repeated runs, and though their repetition does make each one feel less of a thrill, their sheer number begins to impress. Harriet is not a slavery movie. Harriet is a freedom movie. It is a showcase for resilience, and hope. It’s also a reminder of the kind of impact one single person can have.

To that end, Cynthia Erivo shines as its star. Harriet may not be a complete biopic, but it is a fascinating origin story for one of history’s greatest super heroes. If Erivo isn’t talked about at Oscar time, it would be a crime.