Marianna Bassham’s brilliant disguises in ‘People, Places & Things’

Marianna Bassham in "People, Places & Things" at SpeakEasy Stage Company.Nile Scott Studios

Drama is less about what happens than whom it happens to.

Take Duncan Macmillan’s “People, Places & Things,” now at SpeakEasy Stage Company under the direction of David R. Gammons.

The play’s protagonist is Emma, an actress and recovering addict — or, to be more precise, an addict ambivalent about, and sometimes actively resisting, recovery.

Sound familiar? It should. For all the trenchancy of Macmillan’s writing and the bravura of Gammons’s staging, the overall trajectory of “People, Places & Things” is a much-traveled one.

But Emma is played by Marianna Bassham, and that makes all the difference. It usually does.

Bassham brings her trademark blend of technique, fearlessness, all-in commitment, and a gift for intensely individualized portraiture to the role, with that last quality especially crucial as we follow Emma’s jolting journey to and through rehab.

If there is a seen-it-before quality to a scene in “People, Places & Things” — say, in a group therapy session — Bassham burns through it with the specificity and urgency of her portrayal. She gives us a clear sense of what would be lost, and why it would matter, if Emma can’t kick her dual addictions to alcohol and drugs and pull herself out of her self-destructive spiral.

That long-in-the-making downward spiral accelerates dramatically in the play-within-a-play opening scene, when Emma melts down onstage during a performance of Chekhov’s “The Seagull.” It’s off to a rehab facility, where the actress at first identifies herself as Nina, the “Seagull” character she was playing. All Emma knows is performance, a variety of guises and disguises she employs onstage as an actress and offstage as an addict. (Jeffrey Petersen’s scenic design artfully suggests the linkage between the two.)

There’s a fundamental wobbliness to Emma’s identity, a destabilizing fluidity to her sense of self that is either a cause or an effect of her addiction — and either a cause or an effect of her chosen career.

Emma knows she needs help, but she resists what she sees as the delusions of control endemic to the 12-step recovery process. She views life as irredeemably chaotic and random; in her self-justifying moments, she sees self-medication as a way to cope with the pain of that knowledge. She rejects with particular ferocity any suggestion of a spiritual component to her treatment.

From left: Nael Nacer, John Kuntz, and Marianna Bassham in "People, Places & Things."Nile Scott Studios

So Emma butts heads with a doctor and a therapist, both played by Adrianne Krstansky; with a stern but compassionate staffer named Foster (Kadahj Bennett), a former addict himself; and with a fellow patient named Mark (Nael Nacer) who sees the desperation beneath Emma’s deflections and defiance, and challenges her to jettison her protective pose. Mark knows that getting clean means getting honest. Also on hand, as a walking worst-case scenario for Emma to ponder, is a harrowingly unhinged patient named Paul (John Kuntz).

There’s a devastating scene late in the play where Krstansky and Kuntz also portray Emma’s mother and father. In that scene, the question of causality surfaces from the depths of “People, Places & Things” with the suddenness of a shark attack.

The talent of the above names alone is enough to make the SpeakEasy cast an embarrassment of riches, but the production also features in small roles a host of actors — Victor L. Shopov, Josephine Moshiri Elwood, Shanelle Chloe Villegas, and Sharmarke Yusuf, who have shone in much bigger parts over the years. (Also in the cast and ably holding her own is Parker Jennings, currently a senior at the Boston Conservatory at Berklee.)

Few directors can engineer the trip across the border from real to not-real with more bracingly discombobulating theatricality than Gammons, who has guided some of the most memorable SpeakEasy productions of the past decade, from “Hand to God” to “The Whale” (starring Kuntz and Elwood while she was still a student at Emerson) to “Red” to “The [Expletive] with the Hat.”)

Gammons keeps the emotional temperature high and the coming-apart-at-the-seams vibe constant in “People, Places & Things.” This is especially so during the hallucination scenes, which Gammons and his design team (lighting designer Jeff Adelberg, sound designer David Wilson, and video designer Adam Stone) turn into genuinely searing experiences.

As for Bassham, taking her excellence for granted would be easy at this point. But it would also be a mistake. Especially after the uncertainty of the past two years, it’s important to recognize that the career she has built on Boston stages has been something special.

Make that “is building.” The present tense is definitely required. How great is that?

PEOPLE, PLACES & THINGS

Play by Duncan Macmillan. Directed by David R. Gammons. Presented by SpeakEasy Stage Company. At Roberts Studio Theatre, Calderwood Pavilion, Boston Center for the Arts. Through March 5. Tickets start at $25. 617-933-8600, www.speakeasystage.com