Marin Ireland’s new play, “Pre-Existing Condition,” doesn’t come with trigger warnings; it barely even comes with a marketing description. The show’s website says that it’s about the aftermath of “a life-altering, harmful relationship,” but doesn’t explicitly mention domestic violence.

Let’s state right up front, then, that physical abuse is this play’s catalyst. And that the Connelly Theater Upstairs in the East Village is a tiny space, where if the performance became overwhelming it would be difficult for an audience member to leave unobtrusively.

Does it seem overly delicate to foreground that? For a less potent playwriting debut, in a less shattering production, it might not be necessary. But in Maria Dizzia’s quietly unadorned staging, and with a superb four-person cast that at the moment stars an emotionally translucent Tatiana Maslany, watching this play is like seeing its author open up her rib cage and show us everything.

The central character, whom the script calls A, is struggling to put herself back together after a breakup with a man who hit her. The trauma has been consuming her, against her will and for longer than she would have thought.

“I feel like I’m becoming the villain,” A tells her therapist. “I’m becoming this obsessive vengeful figure, because he said he’s sorry, so I’m the problem now.”

The therapist (a sublimely comforting Dael Orlandersmith) points out, “His voice is still in your head.”

An impressive rotation of actresses — Maslany, Dizzia, Deirdre O’Connell, Tavi Gevinson and Julia Chan — is slated to inhabit A during the run: a clever way of signaling universality while adding box-office cachet in these uncertain times for theater. (More on that below.) An equally strong lure is, frankly, the gossip factor: Ireland’s own experience of domestic violence a dozen years ago in her relationship with the actor Scott Shepherd, when they were appearing in a show with the venerable Wooster Group.

What makes “Pre-Existing Condition” so powerful, though, has nothing to do with that. It is A’s Everywoman nature, combined with the vulnerable physicality that’s so evident in such an intimate space: her breath, her welling tears, the placating smile she puts on like a demure piece of armor when she runs the risk of upsetting a man.

Maslany, in the role only through Thursday, performs with script in hand (the director’s choice), yet she wears her character as easily as A does the button-front boyfriend shirt that envelops her for much of the play. (Costumes are by Enver Chakartash.) Maslany’s A is wry, raw and somehow blurred inside, as if her very core had been knocked out of focus.

She doubts herself, blames herself, is fearful in ways she never was before.

“I don’t want the big task of my life now to be ‘dealing with this,’” A says, and certainly there are people in her life who wish she would get over it.

Like the self-righteous, ostensible friend (Sarah Steele) who asks: “Do you want revenge or something? What would make you happy here? You don’t want to ruin his life or anything, right?”

Then there’s an actual friend (Greg Keller), outraged on A’s behalf, who tells her, “We’re too smart and too liberal for someone to just get away with this, in this town, in this community.”

In “this community,” you might hear an implied reference to the world of downtown theater. Perhaps less oblique is the scene where A, scared to listen to her voice mail messages, asks another friend (also Keller) to listen for her and speak the messages “along with them so I know what they said and how they said it” — an echo of a Wooster Group technique for performing with in-ear audio.

“Pre-Existing Condition” doesn’t feel like vengeance, though. It feels like one woman emerging scarred by a not uncommon experience that blindsided her, and badly wanting to alert the others.

Across town in Chelsea, at Atlantic Stage 2, another experiment in rotating casts and universality continues with Tony Shalhoub and Shohreh Aghdashloo taking over the remainder of the run (through June 29) of Shayan Lotfi’s “What Became of Us,” a decades-spanning tale of two siblings in an immigrant family.

Shalhoub’s presence was bound to make Jennifer Chang’s production a hot ticket, and it has. He and Aghdashloo have also made the performance itself a triumph, bringing a depth of emotion and strength of connection that were missing from this two-hander when I reviewed its first cast, BD Wong and Rosalind Chao.

Warm, vivid and funny, Shalhoub and Aghdashloo are theatrical storytellers par excellence, tapped movingly into their characters’ lifetime of memories. Warning to anyone who was left cold by the final monologue last time around: It is now a heartbreaker, just as it’s meant to be.

Pre-Existing Condition
Through Aug. 3 at the Connelly Theater, Manhattan; connellytheater.org. Running time: 1 hour 15 minutes.