Starring Alfre Woodard. Rated PG.

Clemency begins with the starkest image imaginable, with the central character staring at the gurney to which a prisoner is about to be strapped, pending his execution by the state.

Gazing at this taut social drama is veteran warden Bernadine Williams, played by Alfre Woodard, one of the more undercelebrated of our finer film actors. Having already presided over 10 state killings, Williams soon witnesses another: a botched job on a convicted killer that takes 10 excruciating minutes out of our lives, and all the minutes out of his.

A stalwart defender of the system, the warden has lately been ignoring her partner and spending downtime with bottles of scotch. Even given the obvious strain on the warden’s personal life, it’s not clear how the couple’s problems illuminate the issues at hand. But the domestic aspect gradually takes over, and it turns out to be the kind of movie that has a wedding-anniversary scene only so things can go terribly wrong.

Wendell Pierce plays the long-suffering hubby, a popular schoolteacher whose substance is best revealed in his classroom reading of a key passage from Ralph Ellison’s Invisible Man. This also serves as an elegy for the black and brown men pulled into the prison-industrial complex, represented by an armed robber who may or may not have shot the cop he was convicted of killing.

As played by impressive Aldis Hodge, this prisoner has a natural gravity that pulls you in. When his last appeal for clemency, facilitated by a weary civil-rights lawyer (West Wing’s Richard Schiff), falls through, the prisoner shuts down. Thus, he loses his voice, as well as his visibility, in the script from Nigerian-American Chinonye Chukwu, here directing her second feature.

Apart from a few superfluous nightmares and premonitions, the filmmaker’s commitment to utter seriousness is admirable, if ultimately stultifying. What sticks are the day-to-day penitentiary scenes, which show the truly deadening effects of a place where mortality is front and centre at every moment. Death row is generally the safest, quietest realm for both guards and prisoners; there’s nothing left to fight about, or even to say. But the moral, emotional, and spiritual cost of that silence cannot be counted.