Owen O'Neill/Absolution, Assembly@George St, Edinburgh

Owen O'Neill has been performing stand-up comedy for over 20 years. A poet and a writer of nearly a dozen one-man plays, his first film was a dark comedy about priests and the IRA. He returns to his Emerald Isle roots and to the priesthood in his new one-man show, Absolution.

Let's be clear, however, it is not – as advertised – "blackly comic... dangerously funny". Nothing could be less amusing than this dissection (sometimes literally) of a handful of abusive Catholic priests. Each has perpetrated terrible crimes against children and, as the unnamed protagonist, O'Neill becomes the "avenging angel" meting out punishment where the Church and, indeed, whole villages of parishioners, have turned their backs.

It's not easy listening. O'Neill's graphic descriptions of each paedophile priest's sadistic sexual activities, is followed in turn by the narrator's account of their bloody deaths, including that of the priest who – unable to commit the sin of suicide – welcomes his imminent release from this life. Directed by Rachel O'Riordan (acclaimed for her direction of Alex Higgins's biopic, Hurricane), O'Neill is compelling, combining dispassionate accounts with a barely suppressed pent-up rage so that the twist in the final moments is even more surprising.

To 25 August (not 11) (0131 623 3030)