We’ll bet you a future $20 bill that you won’t want to miss Wednesday’s episode about Harriet Tubman on WGN America’s “Underground.” Aisha Hinds plays the famed abolitionist with a command performance certain to have the Emmys buzzing.

AP TV columnist Frazier Moore writes:

Harriet Tubman, who escaped from slavery in the antebellum South to become a leading abolitionist, is best known today as a righteous figure and the future face on the $20 bill.

But for viewers of “Underground” this season, Tubman has come to life as a character on this drama about the treacherous journey to freedom along a secret network of safe houses that came to be called the Underground Railroad.

Now Tubman is the focus of something special, even unprecedented in episodic TV, with this week’s “Underground” episode. It will pause its overarching narrative for a night to let Tubman tell her own story in the form of a solo performance. More specifically, Aisha Hinds, who this season has portrayed Tubman, will deliver a powerful, passionate episode-length oration channeling Tubman.

For Hinds, it was “an honor and a call to duty.” The episode will premiere on WGN America on Wednesday at 8 p.m. EDT, with back-to-back repeats continuing through a replay at 1 a.m. EDT.

The episode is set in what appears to be a remote barn or storage shed where, some night in the late 1850s, a couple dozen sympathizers have gathered furtively to hear from this champion of freedom.

The script, written by series co-creator Misha Green and Joe Pokaski, draws on Tubman’s history and words.

Tubman calls slavery “the next thing to hell” and likens the taste of it to “all your teeth made of copper.”

Born into slavery at its most brutal extreme, she speaks of how initially she “spent all my time knowing things instead of believing them. And that’s the first step to truly being free, when you can see past all the things that you know and believe something better. It ain’t easy, but that’s the work that must be done.”

Stirringly Tubman recounts the work that won her freedom when finally she crossed the line into Pennsylvania. But the work wasn’t done once she escaped. Over and over, she returned to the South to lead others to safety.

“There ain’t no negotiations on freedom,” she declares. “Big or small, there ain’t no compromises, no half-measures .. Cause a country built on bodies will always need more for the slaughter.”

This remarkable episode was shot, like the rest of “Underground,” in Savannah, Georgia. Despite airing as the sixth of the 10-episode season, it was the last episode shot, during the final three days before production wrapped last November.

“Usually an episode would take six to eight days,” notes Hinds, who received the first half of the 45-page script just 10 days beforehand, and the other half a few days later. Could she possibly learn all that dialogue in such a short amount of time?

Day One called for filming the first two acts of the hour’s total of five.

“I laugh about it now, but I was so anxious,” she confides.

As a backup system, the producers arranged for her to wear an earpiece, with Green standing by to feed her any needed cue.

With this arrangement, “I breathed a sigh of relief,” Hinds recalls. But to her dismay she found the earpiece emitted a distracting level of static.

“I took a moment, I took a breath, and I removed the earpiece,” she says. “In that moment I knew that I had to depend on nothing else but Harriet Tubman. And every single word came out. That’s when I felt confident that Harriet had this.”

What Hinds entered was a state “where the brain emptied itself, and I could really feel her presence pushing the story out of me. Those were the divine moments, where I honestly can’t take any credit for whatever the performance is, because it almost became like I wasn’t even there.”

But Day Three brought an even greater challenge. There were just seven pages left to shoot, but that scene was being staged in a single take. No cutting.

“So every time I made a mistake, we had to stop and go back to the beginning. There were a few times I felt like I was going to break.”

She didn’t, “and when we finished that day, I think we were unified as a company, unified as human beings in a way I’ve never experienced in a production in my life.”

Now, while owning up to a few butterflies, Hinds awaits the finished product, which she hasn’t seen.

“I want to experience it with the audience,” she says, inviting everyone to watch: “Harriet’s spirit is necessary to revisit at such a time at this.”