The Dead Wait, Park Theatre

A single movement is all it takes. A wounded man is held at gunpoint, and instead of cringing away from the inevitable bullet, he lifts his head and looks his would-be executioner in eye. This simple gesture does not just save his life – it sets in motion a drama that will ultimately consume the lives of everyone caught up in it.

This pivotal confrontation takes place in the rubble of a village, between black freedom fighter George Jozana and white South African soldiers Papa Louw and Josh Gilmore, during the civil war in Angola. Having decided to keep Jozana alive, the Afrikaans officer Louw (below right) orders Gilmore to carry the wounded man the 50 kilometers to the border, claiming he needs to interrogate Jozana for crucial information about the insurgency. What follows is a battle, to be sure, but of the psychological kind as Louw and Jozana vie to win the heart and mind of the young, callow private as he struggles towards safety.

Paul Herzberg's play was first performed in 1996 in Johannesberg and received its British premiere at the Royal Exchange in 2002. It is revived now in a new version – Herzberg has largely freed it from its specific historical context, setting it now just in "the past" and "the present". He did this to emphasise the timelessness of the drama, and its continuing relevance as present-day South Africa continues to try and overcome its past. It works: without the historical detail, the interplay of power and tragedy is utterly compelling.

Herzberg was originally inspired to write The Dead Wait by his own experience as a South African conscript in Angola in the 1970s. His performance in this version as Papa Louw is outstanding – everything from his pitch-perfect Afrikaaner accent to his devil-may-care physicality compels. His interactions with Gilmore, the young private under his command, are especially good with Herzberg leaping from teasing to torture with great facility. In response, Austin Hardiman manages to squeeze both callow confidence and vicious anger from a part that exists mostly for others to duel over.

Adelayo Adedayo, making her stage debut here after great success as Viva in BBC3's Some Girls, is very well cast as the abandoned daughter of Jozana, the freedom fighter. Despite a very contained stage presence, she manages to dominate the scenes in which an older Gilmore seeks her out to try and apologise for his role in her father's torment.

This is a play that exploits every difference, big or small, and is superbly relentless in doing so. Gilmore and Louw are both white, to be sure, but the fact that one is of British origin and the other Afrikaans is a large part of their conflict. Maynard Eziashi's smooth, sage-like Jozana is the clear outsider, but as such he is at liberty to point out the obvious. When Gilmore boasts of his prowess as an athlete, saying that there is no faster sprinter in South Africa, Jozana corrects him with a casual "nobody white". Apartheid may have ended and the civil war may be over, but this play still shocks, and rightly so.

• The Dead Wait is at the Park Theatre until 1 December