Writer-director Alaesha Harris makes a furious feature film debut with “Is God Is,” an ugly, unblinking slice of African American Gothic horror as relevant as a headline and as timeless as a parable.

It’s about two fire-scarred sisters “always on the outisde looking in” given the chance and the responsibility to avenge themselves and their family on the man who did this to them. One is hardened enough for the quest, and the other too compassionate or just too beaten down to be.

Blood will be shed on a north to south, coast-to-coast quest to track down the father who burned their house, with them and their mother in it, got away with it and thrived, guilt-free in a new life. Nothing will be simple and little’s going to be pretty in this Old Testament styled manhunt/man-punish odyssey.

Racine and Anaia are twins, bonded since birth in ways the movies often treat as supernatural.

“If one finds trouble, the other can feel it,” one of them narrates. They can communicate telephatically. And if you pick on one, and you’ve got to deal with the other.

Racine, played with a cold-blooded resolve by Kara Young (of TV’s “I’m a Virgo”). is the tough one — petite, with most of her scars on her arms and torso. But God help you if you call her more badly-scarred sister Anaia (Mallori Johnson of “Steal Away”) “ugly.”

They’ve grown up in the foster care system, abused and neglected and unloved. These days, they can’t even keep custodial jobs. ‘Cine takes any second glance as an insult, any repellent look as an outrage.

Then they get a summons they were never expecting. Their mother, whom they’d been told died in that long-ago fire, is alive down Virginia way and breathing her last.

But mother Ruby, played through scar tissue and gritted-teeth by Vivica A. Fox, doesn’t have a tearful reunion in mind. She knows who did this to them and has a notion of how to find him. There’ll be no “forgive and forget.” Ruby declares she’ll have “no peace until I know he’s gone.”

She is their mother, the one who “created” them, “God” to the two sisters. Her word is the law.

Racine’s violent temper tells us straight off that she’s down for this “mission.” Anaia isn’t, but is too weak to resist her sister’s furious focus and too loyal to let her take on this quest by herself.

They will encounter figures worthy of a Homerian odyssey in their travels — their father’s faith-healer/preacher second wife (Erika Alexander), his beautiful, kept-in-comfort third wife (Janelle Monáe), assorted step siblings and dad’s old and mute (tongue taken out) lawyer (Mykleti Williamson).

But little that they experience prepares them for The Man (Sterling K. Brown) himself.

The script’s narrative is somewhat static, even as it’s on the movie. And its messaging is direct to the point of simplistic.

But this cast plays the hell out of this violent parable about what one endures, who one believes caused it, the need for revenge and the cost of giving those who deserve it their comeuppance.

Fox has her best role in years and registers grief eaten up with outrage under layers of makeup and in pre-fire flashbacks. Young practically seethes off the screen, Johnson gives the movie its humanity, with Alexander, Monáe and Williamson adding different shades to the black and white, good and evil simplicity of the plot.

And Brown shows up to bring it all home, delivering a character study in “the villain’s point of view” — cold, calculating, unsentimental, the “monster” any horror film simply must have to come off.

Rating: R, graphic violence, profanity

Cast: Kara Young, Mallori Johnson, Vivica A. Fox, Janelle Monáe, Mylkelti Willaimson and Sterling K, Brown.

Credits: Scripted and directed by Alaeshea Harris. An Amazon/MGM release.

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