Remembrance Day, Royal Court Theatre, London

Watching Aleksey Scherbak's extraordinarily powerful Remembrance Day, I kept thinking how deeply both Mikhail Bulgakov and Sean O'Casey would have appreciated its human and artistic qualities. Scherbak, like them, has the gift of showing how appalling tragedy and hapless comedy restively malinger in a perpetual, untidy coexistence, especially in societies that are corrosively divided.

The play's simple, eloquent staging further intensifies the mixed moods of black humour, desolate pathos and dark foreboding in Michael Longhurst's splendidly acted production. The play is set in a block of flats in the Latvian capital of Riga. Living cheek by jowl, though not on speaking terms, in stark apartments are figures who betoken the bitter legacy of the country's contentious past. In the sharply paradoxical stage picture created here, it's as though their separate living quarters have been superimposed on each other so that implacable foes and pained moderates drift around the one communal space, unwittingly sitting side by side at a kitchen table, and promiscuously arriving and departing through the same row of front doors on Tom Scutt's uncluttered, vivid design.

The dramatic events are triggered by Latvian Legion Day, the annual procession through Riga of Nazi Waffen SS veterans and other native Latvians in commemoration of those who fought against the Soviets even if that meant getting into bed with Hitler. Preparing to join in her first anti-fascist demo is young Anya, whose unnerving zeal and the emotional hurt and confusion that underpin it are brilliantly communicated by Ruby Bentall. Her parents are ethnic Russian and, while accompanying her to keep her out of trouble, the girl's father, Sasha (a movingly troubled Michael Nardone), gives an impromptu interview to a pro-Russian television channel and makes a plea for toleration, arguing that it is time "to end this uproar over these old men". He's falsely branded a Nazi sympathiser and it's not long before swastikas are painted on their doors, his wife sacked, his daughter murderously alienated from him, and his apolitical son embroiled in street violence.

Written under the auspices of the Royal Court's remarkable international department and robustly translated by Rory Mullarkey, Remembrance Day superbly complicates your sense of the intractability of the situation. There's a gloriously tragicomic and O'Casey-esque double-act between an unrepentant nationalist veteran (Sam Kelly) and his more sensitive sidekick (Ewan Hooper) who points out that he has fought in four armies in the course of his life. It's typical of the play's wrong-footing myriad-mindedness that just when you tensely think it's an assassin's knock at Sasha's door, it turns out to be the Kelly character paying a reluctant call to thank him for medical help. The play is, by turns, heartbreaking, beadily satiric and humorous.

Can we let go of old animosities without betraying the victims of past injustice? I don't think the play straightforwardly endorses Sasha's brooding tolerance. Certainly, it shows us how some unlovely young activists in Latvia keep the rifts open as a cynical career move. Unreservedly recommended.

To 16 April (020 7565 5000)