After the fall of the Third Reich, Josef Mengele – the notorious Nazi doctor known as the 'Angel of Death' – evaded capture and fled to South America, where he lived under a pseudonym until drowning off the coast of Brazil at the age of 67. In Mengele, he washes up on a beach, having been saved by a mysterious woman whose gentle questioning and flattery spurs him to defend his actions during the Holocaust.

Tim Marriott gives a powerful performance as Mengele, capturing the doctor's bombast, narcissism and unrepentant self-delusion as he attempts to 'correct' his legacy. He blusters through a litany of excuses: it was for the greater good, it was government sanctioned, nature's chaos must be brought to civic order. He is rendered human without being humanised; his sociopathic logic made monstrous as well as unsettlingly familiar.

For that is Mengele's most resonant message: his xenophobic ideas, while extreme, continue to proliferate today, and such evil can emerge from the most mundane of sources. The play does a fine job of intercutting his ravings with documentary footage from the Holocaust – a formidable counterpoint to Mengele's historical revision, and an ominous warning to us all.

Assembly George Square Theatre, until 26 Aug (not 9, 11, 13, 15, 17, 19, 21, 23, 25), £10 (£9).