“Everything is disappearing.”

The succinct, disturbing statement escapes Ned’s mouth in a hushed tone  — part panicked confession, part plea for help — as Dale, Ned’s longtime friend and neighbor, prepares to turn in after an innocuous evening of swilling beers that verges on becoming far too emotional.  

The statement — and its implications — lingers in the mind, not as a profound existential observation, but as a fact. One by one, each and every object he cared about, from cuff links given to him by his wife to a cricket bat from his youth, has begun to vanish.

This is the crux of British dramatist Jez Butterworth’s play, “Parlour Song,” which is being performed by the Quantum Theatre company through Nov. 24. As Ned (Cameron Knight), a demolition expert, struggles to make sense of the sudden and widespread disappearance of his things, he is forced to contend with the much larger disappearances in his life — the loss of intimacy with his bold, attractive wife Joy (Sarah Silk) and any sense of internal balance that he might have once felt in his mundane, middle-class existence.

The only person he can cling to is his endlessly charismatic friend Dale (Brendan McMahon), who, in spite of his supposed stability, finds himself drawn into the blast radius of a domestic life that’s primed to implode.

This is not to say that the play is all drama, however. The piece is riddled with wry humor and rapid banter as the players attempt to ignore the pressing issues before them. Moreover, it’s the vacillation between these instances of clever comedy and darker undertones that make the existential panic of the play so meaningful.

With vivid performances, thoughtfully crafted direction and an ingenious use of space and lighting, Quantum Theatre’s rendition of the play palpably exposes the strain created by holding up a happy facade while the underpinnings of one’s life begin to give way.

Staged in a Waterfront building that formerly housed The Pittsburgh Burger Company, the immaculate and unnervingly generic nature of the set is perhaps the most striking element of the performance. On stage before the audience lies the entirety of the setting — no changes are made to the set, and the actors rarely leave.

When they are not literally present in the scene, the actors are relegated to another part of the stage, as though their presence still hangs over the events taking place.

The effect of director Martin Giles’ decision to stage the play in this manner cannot be understated. As Ned and Dale share a laugh, Joy is visible through a window pane, staring numbly into space and drinking yet another glass of white wine. When Dale and Joy play a game of scrabble, Ned’s outline is visible as he sits in darkness, alone.

The subject of middle class ennui has been explored ad nauseam by every playwright, novelist, screenwriter and musician who has so much as glimpsed a white picket fence. Butterworth is well aware of this constraint on his work, and he has delivered a play that probes this ubiquitous suburban loneliness while avoiding heavy-handed admonishments of modern life.

His characters aren’t avant-garde. They’re quietly and painfully human. These aren’t characters pulled from Jean-Paul Sartre and dropped into a middle-class British apartment — they don’t deliver lengthy speeches about the philosophical problems surrounding their lives. When, over dinner, Ned — sporting a forced, nearly crazed smile — tells Joy about his unnerving experience exploring an empty development filled with houses exactly like theirs, he notes that “it makes you think.”

After a beat, Joy, already on her second glass of wine, asks “About what?” The manic grin melts away as he realizes that he hasn’t the faintest idea what any of it means.

It’s with this opacity that Butterworth grounds the play and gives the power to the performances — particularly Knight, whose desperate, nervous and eerily chipper version of Ned will undoubtedly resonate deeply with anyone who has witnessed a loved one bear similar torments. Though Butterworth gives us a glimpse of their internal life, we never see it all. This creates immense humanity within the characters — we may see the way they suffer, but we will never fully understand why.