“Resurrection Road” is a mediocre Civil War B-movie that lapses into a seriously bad supernatural C-picture for the third act.

That’s also when Michael Madsen, King of the C-movies, makes his mark.

There’s a little promise in the premise — Black Union soldiers sent to disarm a Confederate fort in Arkansas, led by an escaped slave/soldier promised “40 acres” if he takes on this suicide mission, and a hangman’s rope if he doesn’t.

With Civil War movies on an indie film budget, one fun exercise when watching them is looking for anachronisms in the uniforms, firearms, settings and colloquialisms. Yes, there were Confederates who used lever-action repeating rifles. Yes there were truss bridges to cross, but no, “dynamite” wasn’t invented until 1867.

Hard to know if ex-slaves turned soldiers used “mother-f—er” as much as this fractious sextet does.

Malcolm Goodwin plays Barabas, the “convict” busted down to private and imprisoned until General Craven (Jeff Daniel Phillips) shows up with an offer he can’t refuse. Take five other soldiers to your old stomping grounds in Arkansas. Disable the fort’s big guns.

So forget the nightmares you still have about being enslaved by the sadist Quantrill (Madsen), what it cost you and your family. Get a move on “you filthy Black son of a…”

Yeah, there were racists on the Union side, too.

Barabas regains his sergeant’s stripes (we assume) to take command of a motley crew played by Okea Eme-Akwari, Furly Mac, Randall J. Bacon, Davonte Burse and Bryan Taronn Jones. It doesn’t take long for things in “this s— detail” to go wrong, and then more wrong.

A Cherokee survivor of a massacre (Triana Browne) joins their thinned ranks, a handy someone to have around when the detail runs across evidence of gruesome deaths and tales of supernatural “bad juju” goings on in that fort.

Writer-director Ashley Cahill probably needed that supernatural element to sell this screenplay pitch. But it didn’t sell for much. Look at the fort, when the stragglers from the unit finally come to it. It’s digitally painted silhouettes and big, non-functioning (digital) cannon.

Madsen’s Quantrill arrives and things go further South corresponding with that.

Goodwin isn’t bad even if Browne isn’t experienced enough to overcome the caricature her character is and Madsen’s just here for the hat and the ham.

It is what it is and is never more than that. But it’s a damned shame that nobody is satisfied with a simple “suicide mission” combat period piece any more. You’ve got to go “Overlord” or “Sinners” or whatever, because history, even fictionalized “Guns of Navarone” history, isn’t enough.

Rating: R, graphic, bloody violence, profanity

Cast: Malcolm Goodwin, Triana Browne, Okea Eme-Akwari, Furly Mac, Randall J. Bacon, Davonte Burse, Bryan Taronn Jones, Jeff Daniel Phillips and Michael Madsen.

Credits: Scripted and directed by Ashley Cahill. A Saban Films release.

Running time: 1:17