Gusta Johnson and Reba Askari appear in a scene from “Mary Jane.” Katie Day photo

The Mad Horse Theatre Company has a history of choosing to present plays that place their characters in unusual situations. Netherworlds, twisted histories, surreal dystopias and cartoonish conundrums all have been presented at one time or another at the company’s intimate South Portland venue. With its latest production, though, the intrepid troupe has ventured into the mostly unenhanced reality of everyday life, at least as it is for a significant minority of people.

Amy Herzog’s powerful and moving “Mary Jane” chronicles the trials and tribulations of parents whose lives are essentially taken over by the need to care for a chronically ill child. Mad Horse delivers one of its best productions with this alternately gut-wrenching and life-affirming play.

The play takes us into the life of the title character, a single mom whose son (never seen but always close, just offstage) suffers from cerebral palsy and related complications. Mary Jane tries hard to deal with the toddler-age boy’s extensive physical challenges while keeping their small household economically and spiritually afloat. Although she has some in-home nursing help, the tasks of assuring that he’s fed, clean and, most importantly, kept breathing occupy most of her time and energy.

Mad Horse regular Reba Askari gives an extraordinary performance as Mary Jane, a likable young woman whose aspirations to become a middle school math teacher have been put on hold after the premature birth of her son, Alex. Within the company’s close-up, three-quarters-in-the-round theater setting, Askari takes us into Mary Jane’s world with all the sweet but frazzled exuberance of a woman aware of, but bravely determined to stay back from, the edge of despair.

We learn bits of the back story through Mary Jane’s conversations with her sympathetic building superintendent, Ruthie (Tootie Van Reenen); a supportive visiting nurse, Sherrie (Elise K. Voigt); the nurse’s young niece Amelia (Emily Grotz); and Brianne (Gusta Johnson), a young woman learning the ins and outs of caring for her own sick child. Each offers support through practical input as well as encouraging some of Mary Jane’s coping strategies. Mary Jane’s proverbial “village” helps her along with a lot of warmth and caring.

Alex’s deteriorating condition takes Mary Jane to a hospital waiting room in the second act. There she encounters a diverse collection of new characters (all actors, except Askari, doubling) to help her combat this chilling new institutional setting. Another mom commiserates while a doctor, a music therapist and a chaplain are drawn by Mary Jane’s plight to overstep their professional bounds just a bit to assist her in her search for broader, spiritual relief.

Director Stacey Mancine Koloski, with fine writing with which to work, has given the players the freedom to personalize their roles and the results are outstanding. They become these people.  The only quibble with the production might be with the use of some soundtrack music (a live song delivered by Grotz, however, works nicely). There’s no need for extra dramatic lift when you’ve got players giving performances that carry their own weight so well.

Note: A portion of the ticket sales from the Sunday, Nov. 17, performance of “Mary Jane” will be donated to The Barbara Bush Children’s Hospital.

Steve Feeney is a freelance writer who lives in Portland.