John Nayagam and Keith Dunphy in Under the Black Rock [Gregory Haney]

THE signing of the Good Friday Agreement in 1998 helped end three decades of violence, and brought stability to Northern Ireland. Set in Belfast, just before the agreement was ratified, Tim Edge’s gritty drama serves as a timely reminder of how violence breeds violence.

Under the Black Rock explores the various ways young people were drawn into extremism, often persuaded by family loyalties. The experiences of the divided Ryan family, living under the shadow of the Black Mountain, are at the heart of Edge’s play.

Cashel Ryan (John Nayagam) has long been a member of the IRA with another old-timer Brendan (Glen Wallace). After Cashel’s son Alan (Jordan Walker) dies in police custody, his daughter Niamh (Evanna Lynch) signs up to the cause. Their mother Sandra (Flora Montgomery) looks on in dismay as her children are pulled into the violence.

Niamh joins a new cell led by Jimmy Lynch (Matthew Blaney) and under the careful watch of a steely female commander (Montgomery). When things start to go wrong they must weed out the informants, whatever the cost.

Director Ben Kavanagh squeezes out every last drop of tension from Edge’s drama. The play opens with four characters wearing hoods. A menacing black rock is suspended over the stage throughout the performance. A torture scene is particularly gruelling.

It’s difficult to know who to trust and suspicions abound between the various members of the cell.

Characters like Father Paul Flynn (Keith Dunphy) and gossipy churchgoer Mary (Elizabeth Counsell) reveal surprising sides.

It’s brilliantly acted, often gripping theatre, and Edge keeps us guessing until the very end. But some scenes are graphically brutal, so not for the squeamish.

Until March 25
arcolatheatre.com/