It's as a great onrush of sometimes laugh-out-loud verbal virtuosity that Emmet Kirwan's very talented two-hander bowls you over. On a stage empty but for a couple of microphones, Kirwan and Ian Lloyd Anderson play off each other with a brilliant rhythmic rapport and a keen instinct for when to vary the pace and the dynamics as the material shifts around a variety of modes. There's the swagger and linguistic self-intoxication of rap and a kind of vernacular concrete poetry that you can almost see materialising in mid-air as it is uttered. There are passages that reminded me a bit of Martin Amis in their openness to the low farce of bodily life and in their aplomb at comic exaggeration – “It's a napalm explosion in the south-east Asian jungle that is my nose hair” reports our hero after he's snorted up a wrap of ketamine. And there are quieter, fully dramatised scenes that have a huge emotional charge and prove that Kirwan's power as a theatre-maker does not depend on constant verbal pyrotechnics.

The author portrays Jason, a Dubliner in his late 20s, whose fruitless ambition is to do the warm-up set for one of the visiting star DJs at a rave. We follow him over a drug-fuelled weekend in the capital's scuzzy club scene as he gives his mind a chemical kicking and stumbles through a series of misadventures that include a police bust, a humiliating run-in with his ex-girlfriend and tasting the penalties of being a mere gopher for a celebrity DJ who puts a hole in the landlady's wall: “Ten minutes later I'm standing in the street with a six-foot speaker, shepherding the expelled exodus of revellers to the promised land of the Bernard Shaw like some sort of techno Moses”.

Jason can be so droll and perceptive about his unenviable lot but his ability to see it at a distance doesn't mean that he's not firmly stuck in it. He keeps spotting (or so he believes) his doppelganger. And there are crucial chance encounters (are these in his mind too?) with Daniel, his university-educated older brother who is now a homeless heroin addict (beautifully played by Anderson --- who also creates a cascade of cameo characters). The siblings haven't seen or spoken to one another in three years. These excellent scenes establish that Jason, who says he plans to come off recreational drugs in three years, is in denial about how much he has in common with Daniel. But to put it that way would misrepresent the tone of the episodes that are funny, awkward and heart-wrenching as the painful twist of intimacy and hurt, love and resentment in their relationship now is exposed. During the police bust, Jason had to dump his wallet and he's farcically reduced to begging money from his homeless brother who only has a sock full of change.