Intensely bleak and bleakly beautiful, Maria Irene Fornes’ “Mud” gets down and dirty with the dark side of human nature.

Directed by Alexis Carra ’03, “Mud,” a one-act play, is a brief but memorable wallow in a world where words — clumsily spoken, sounded out from books, hurled out in anger and longing — are the only possible way to break the chains of a near-savage existence.

Mae (Kate McGovern ’03) is a hardened young woman living in stark poverty with Lloyd (Jacob Brogan ’05), her uneducated not-quite-brother, who is slowly rotting away from a mysterious prostate disease. Their bubble of festering hatred and love is ruptured by the arrival of Henry (Sam Brandao ’03), a soft-spoken, semi-educated man who, at Mae’s urging, becomes her lover.

The power struggles between Lloyd and Henry intertwine with Mae’s own fight for knowledge and sanity. The relentless push and pull between the three characters’ conflicting desires creates a strange menage a trois.

It is the tension within this threesome, overflowing with bitterness and despair, that drives the play through a series of increasingly violent confrontations to its tragic, but not particularly shocking, climax.

McGovern gives a masterful performance as the frustrated and beaten-down Mae, the heart of the play. Pale and luminous, seething with a raw and indefinable thirst — is it for love, knowledge, opportunity or simply freedom? — she seems to alternately fade into the mud-splattered set and to transcend its limits.

Her lines, the most poetic of the play, give “Mud” a dimension of pure beauty that is at odds with the twisted sexuality and mental impotence pervading the characters’ reality. “I’m a hungry soul,” Mae whispers at one point, in a voice alternately devoid of emotion and brimming with it. “I’m a longing soul. I’m an empty soul — It satisfies me to hear words that speak so lovingly to my soul.”

As Lloyd and Henry, Brogan and Brandao succeed in capturing the strange relationship between the two men, who stand at polar opposites of society and even humanity. Henry is the somewhat stuffy, somewhat arrogant pseudo-professional in a collared shirt and tie; Lloyd is crude, smirking and sexually impotent, with the air of an injured and embittered animal. Time and again, they find their roles and fortunes reversing; they are competitors for power over Mae and over their enclosed world, but they seem also to be two halves of a whole, each unable to exist without the other.

Although the material feels by turns fresh — especially in Mae’s speeches — and, especially in the later scenes, a bit clumsy and warmed-over, the three actors infuse their performances with enough power to make us understand the wild passions that drive these characters.

The intimate dimensions of the Off-Broadway Theater literally push the audience up against the very edges of these three characters’ lives, allowing us to see every bit of dirt, every bite of milk-sopped bread, every pore and hair and wild glint of eyes. The sheer despair and barrenness of this trio’s existence is accentuated by the relentlessly monochromatic set (designed by McGovern and Vanessa Wolf GRD ’08), and the uniformly drab costumes by Uyen Thieu ’03.

“Mud” may leave you wanting to take a shower, but its graphic, unwashed, haunting power makes for a eye-opening experience.