The most banal question you could ask about Enda Walsh’s latest play also happens to be the one with which it seems most concerned: what’s it all about? Written quickly, and conceived after a year filled with griefs, it might be Walsh’s most despairing and angry work, yet relies on the tropes of his theatre to the point of self-cannibalism: another room, another trap.

This one takes the form of a waiting room, which, in Jamie Vartan’s design, is overwhelming beigeness: plastic chairs, a Swiss cheese plant, a ticket dispenser, empty fish tank. Here, a young woman (Charlie Murphy) is monitored via CCTV by an anxious young attendant – the new guy. Is the old guy on holiday, she asks? “It’s a little more permanent than that,” Hugh O’Conor pants through a microphone.

Isla has been kept here since childhood – in a room, in a tower, in a city – like a princess in a dystopian fairy tale. She imparts stories down a microphone, or dreams, which her watcher records from a cluttered office and sometimes accompanies with music and visuals. These dreams, she is told, are being made for her beyond the towers. But that doesn’t explain why she has seen people jumping from them to their deaths.

Almost everything in Walsh's play, which he again directs for Landmark Productions and Galway International Arts Festival, is a study in isolation. The aptly named Isla, whom Murphy and choreographer Emma Martin give a girlish physicality, may long for a companion, but nobody interacts directly, divided by screens, recordings or walls.

The same goes for the play’s form, composed of of discrete, disjointed elements. Helen Atkinson’s brooding sound design judders into Teho Teardo’s politely aching compositions, in turn interrupted by abrasive pop songs. (Walsh’s perferred dramaturg is chaos.) A second movement, a frantic dance by Oona Doherty, marks an adventurous departure for Walsh, trusting collaborators to say what words cannot. But for all the command of Doherty’s performance, Martin’s sketch isn’t allowed to be much more than a reiteration of what has gone before: confinement, frustration, outburst, destruction.

This all seems quite deliberate. For the first time, there is something goading about how hard the play leans on very familiar tropes: the eternal waiting, slapstick routines, performances commanded by light and stage apparatus, recorded monologues of elliptical fracture – this is “Beckett bait”, hollering for comparisons Walsh usually plays down. “To implode is never an option,” Isla says, angered by the tug of grief – but that is what the play invites.

There is something aggressive, almost self-lacerating about it, punctuated with rumbling blackouts and bitter self-reference. But this time the absurdity is more despondent, with vague political references to our surveillance culture and power structures of “those keeping and those being kept”, as though explaining Foucault to children.

There is no greater tragedy in Walsh’s theatre than lost childhood. And although Murphy and O’Conor have been given functions here, rather than characters, it is to childhood they both wish to return, when there was innocence and hope. That is what is being mourned here. Erratic, angry, despairing, eruptive and eventually accepting, this is not a play about grief. This is grief.

Runs until July 24