Red Bud, Royal Court, London

The blue-collar pals in Brett Neveu's new play have been gathering at this annual motocross championship in southern Michigan since they were high-school students. Partying on the campsite nearby has become a tradition of getting drunk, chilling out, reliving past glories, and engaging in those ritualised American group games that can look to the outsider more like a way of fending off intimacy than enhancing it. The cry of "Red Bud!" that always finds an echo from other revellers, is meant to express fun-loving high spirits but, with this lot, it increasingly sounds a note of desperation – a faking of what is no longer there.

Reunions are almost as regular a feature of stage drama as homecomings. They provide an excuse for assembling a motley crew of characters and for exploring the toll that time has taken on them. In sorting so much out in advance, they can also feel a shade too convenient as a format. Very well staged by director Jo McInnes, with the audience on three sides of a campsite, Neveu's play – which is set on the 21st anniversary of these gatherings – vividly exposes the cracks in the camaraderie as middle-age creeps up on the frustrated circle, offering in the process, a pungent snapshot of disillusioned blue-collar America.

Indeed, one of the weaknesses of the piece is that the tensions are overt from the outset and the bunch of buddies so far gone in mutual resentments that it's hard to imagine a time when they rejoiced in one another's friendship. And what can barely be conceived can scarcely be lamented. The once alpha-male of the party, Greg (superbly played by a brooding Peter McDonald) arrives already grim-faced with discontent. He used to be a daredevil rider, but this year he has left his bike at home and brought instead his pregnant wife. We are left to infer that impending fatherhood, relatively late in life, has caused him to unravel; precisely why, though, is left under-explored as we watch him treat his spouse (Lisa Palfrey) appallingly and lurch towards drunken self-destruction.

It doesn't help that you'd have to be a saint to warm to these people. The two losers – Jason (Hywel Simons), an unemployed lawn-chemical worker, who has had to sell off everything including his tent, and Shane (Roger Evans), a social worker ignominiously demoted after the accidental death of a child in his care – take needling pleasure in trying to undermine one another. Much mocked for his comparative responsibility, fireman Bill (Trevor White) has reverted to embarrassing cliché by having a 19 year-old blonde, Jana (Isabel Ellison) – a character who comes in handy as an audience for old stories but who is not sufficiently deployed to examine generational difference.

The dialogue is tangy; the ensemble acting terrific; and Jon Clark's expressive lighting tapers eloquently as the proceedings veer into the emotional darkness of the tense, climactic drinking game. But the back story of the group's shared past has no real texture or complexity in this 75-minute piece and so the intimations of tragedy feel unearned. The question Jana asks about the event could be asked of the play itself: "What's the draw?"

To 13 November (020 7565 5000)