By Stanford Friedman

In the surreal HBO drama, The Leftovers, Carrie Coon portrays a mother whose children suddenly and unexplainably vanish. Now, as the title character in this flawless production of Mary Jane at the New York Theatre Workshop, she plays a mom whose child is vanishing very slowly, and she fully understands each precious minute. In one of the best performances of the new season thus far, Ms. Coon tries to maintain a facade of ease over an almost unbearable inner tension, tirelessly coping with her fate and hoping against hope. Surely she will explode or take vengeance. In a lesser play that would certainly be the case. But within the whip smart construct of Amy Herzog’s inspired work, having compassion for others, having a knack for maintaining normalcy, and having a kick-ass employee health plan are enough to keep Mary Jane from going ballistic. Whether or not she is collapsing from within is another matter.

On a macro scale, this is a play about the slow breakdown of imperfect systems. These systems include the nuclear family, the human body, modern technology, medical facilities, higher education, the subway, and religion; but it begins with plumbing. We first meet Mary Jane in her Queens apartment on a morning when the building super, Ruthie (Brenda Wehle), is trying, and failing, to fix a clogged kitchen sink. But soon enough we learn there is a much larger problem in the home. We do not see Mary Jane’s son behind the door of the apartment’s only bedroom. He comes to us only as a series of beeps from medical monitors and that ghastly sound of a suction machine that tells us that a clogged kitchen drain is laughably unimportant.

Ms. Herzog’s cleverest ploy is to begin the play two year’s into Mary Jane’s ordeal. At this point, she has nearly gotten use to her own tragedy, learning the ropes of living with a severely disabled child while mostly maintaining her outward composure. Nevermind the migraine headaches.  As the son’s condition worsens from grave to graver to gravest, we witness which support systems work and which do not, and how she must persevere regardless. Sherry (Liza Colón-Zayas) is her hyper vigilant home healthcare nurse, but she is also the only available nurse who is competent or even willing to take on this assignment. Brianne (Susan Pourfar) is a Facebook acquaintance with a sick child who turns to Mary Jane for guidance. Mary Jane becomes the first cog of Brianne’s own desperately needed support system.

Director Anne Kauffman also helmed the recent Broadway production of Marvin’s Room, making her the foremost authority on dramas involving off-stage dying characters. Here, each scene flows seamlessly into the next with a slow and even pacing that captures the audience. You know you are doing something right when even the smallest of laugh lines results in tension-releasing guffaws. Ms. Kauffman is also not afraid of silences and darkness. One of the play’s most beautiful and contemplative moments occurs when Mary Jane, sitting in the dark, turns on one of her child’s toys which casts an array of stars and moons upon the living room walls.

The supporting cast, all in dual roles, also shine (as does scenic designer Laura Jellinek, whose set magically pivots from apartment to hospital). Ms. Wehle is hilariously dark as Ruthie in the first scene, then spiritually beatific in the final scene as, of all things, a Buddhist hospital chaplain. Ms. Colón-Zayas matches Ms. Coon’s mix of warmth and matter-of-factness as both Sherry and as the doctor who tries to keep Mary Jane’s hopes grounded in reality. Ms. Pourfar’s Brianne is a replica of how Mary Jane must have been when she began this process, and then later she portrays Mary Jane’s near-opposite, a religious Hasidic woman with seven children. Nonetheless, they find much in common during a tender and comedic scene in a “parents room” at the hospital. And Danaya Esperanza brings a skilled awkwardness to both Amelia, who visits Mary Jane’s home at an inconvenient time, and as Kat, a music therapist at the hospital who also picks the exactly wrong time to offer her services.

Mary Jane – By Amy Herzog; directed by Anne Kauffman.

WITH: Carrie Coon (Mary Jane), Liza Colón-Zayas (Sherrie/Dr. Toros), Danaya Esperanza (Amelia/Kat), Susan Pourfar (Brianne/Chaya) and Brenda Wehle (Ruthie/Tenkei).

Scenic design by Laura Jellinek, costume design by Emily Rebholz, lighting design by Japhy Weideman, and sound design by Leah Gelpe; Lisa Ann Chernoff, stage manager. Produced in association with Yale Repertory Theatre. New York Theatre Workshop, 79 East 4th St.,  (212) 460 5475, Through October 29. Running time: 90 minutes.