It’s hard to imagine journeying at a rapid pace through thorny, jungle-like terrain without leaving the comfort of the living room. But that’s exactly the kind of delicious dissonance Threshold Repertory’s production of David Mamet’s Boston Marriage delivers.

The jungle here isn’t made up of tropical plants, but of words. As soon as the two main characters, Anna and Claire, take their places on set, the repartee and double entendres familiar to Mamet fans start flying. It soon becomes apparent that the audience is in for a bumpy ride as this production unfolds. Although the set is a genteel Edwardian drawing room, complete with a fainting couch and chintz curtains, the conversation the audience witnesses between these two women is anything but polite.

Anna, played by Threshold Rep’s artistic director Pamela Galle, and Claire, played by Haydn Haring, are involved in a Boston Marriage, an Edwardian term for a live-in arrangement between two women who may also share an intimate physical relationship. The third point in this play’s triangle is Catherine, the ladies’ much-abused maid who is often the victim of collateral damage from the misdirected anger Anna and Claire sling about the room. The maid, played by Hannah Martin, has a doe-eyed look of innocence that makes her increasingly sharp tongue an unexpected surprise.

As the play opens, Anna sports a new necklace and Claire a knowing smile. Anna reveals that the necklace is from a married “male protector” she has become involved with in return for financial support. Claire, the younger half of the couple, also has news to share. She is “in love” with a young woman and, to Anna’s dismay, she wishes to use their home as a love nest with the object of her affection that very afternoon.

That all happens within the first ten minutes, and as the play progresses, the tone of the conversations between the three women swings wildly from joy and triumph to wheedling and defending to sharp insults and thinly veiled accusations. It soon becomes clear that the two lovers and their maid have a long-established pattern of interacting, and that Anna and Claire are so close that their method of conversing with each other approaches a secret language all their own.

The rapid-fire conversation is also full of funny lines and double meanings, which, judging from the boisterous laughter, the audience had no trouble finding humorous.

Yes, even as all three women say one thing and mean another, it’s obvious that deep down they love each other, even as each struggles to maintain the upper hand and goes to great lengths to get what she wants. “Do you think the soil can keep on giving?” Anna cries at one point, alluding on the surface to the Irish potato famine (she insists throughout that the Scottish maid is Irish), but the audience understands she is talking about herself in her desperation to win back her younger love.

After the first act ends with a shocking revelation about Anna’s necklace and Claire’s love interest, those deeper passions rise closer to the surface as the production careens along to its conclusion. Act II finds the two women abandoning a bit of their earlier venom as they draw together to solve problems at hand and confront fears about losing their income and home, and of Claire losing her chance with her intended lover.

The maid also finds her voice in Act II, abandoning her previous innocence and getting in some well-earned verbal jabs of her own. The power shifts, suddenly, as Anna and Claire realize Catherine has knowledge that could help them out of their tight spot. One of the most delightful scenes in the play ensues as the two ladies converse behind the maid’s back on the fainting couch about how they can use Catherine’s island knowledge to plan a séance designed to rope in the male protector and Claire’s love. All the while, Catherine sits between them sipping sherry out of a fancy glass like the happy cat who swallowed the canary.

Boston Marriage never leaves the drawing room, but it takes the audience on quite a surprising trip. As the final scenes unfolded, audience members were called upon to decode and interpret what was really going on behind Mamet’s dense language — and the unexpected ending revealing a final manipulation certainly caught some audience members by surprise, as evidenced by a few audible gasps and knowing chuckles in the theater.