The House Keeper, Project Arts Centre, Dublin

Mary (Cathy Belton) has just had her home repossessed. Jobless and desperate, and with child services breathing down her neck, the young-ish New Yorker decides to break in and occupy the fancy Manhattan home of a rich old lady (Ingrid Craigie).

The problem is that the eccentric old bat may not be as alone – or as vulnerable – as Mary believed. A warped and desiccated old man (Robert O’Mahony) might just be sharing the digs.

Morna Regan’s new play initially offers us comedic realism, with Belton and Craigie spending the first act trading witty barbs on the disparity between rich and poor. The piece becomes far more interesting when it switches registers and becomes a horror story. That switch is signalled by O’Mahony’s splendidly hammy arrival onstage. The earlier pow-wows about wealth and power take on a mythic scope, and O’Mahony’s venal old wretch becomes an effective – if somewhat clichéd – symbol for a primal corruption at the heart of power.

Unfortunately, neither Regan nor director Lynne Parker embrace the full potential of the plot’s horror elements. Regan’s writing is clever and funny, but every dramatic denouement is verbal rather than visual. Yet it has an irresistible charm and offers plenty of fun, provided you don’t take it too seriously.