Like her classical namesake, Cassandra has trouble getting people to believe her. It's hard even for the audience to take her at her word. Are we to accept as real the faithless lover she chats to in her bathroom? Or is he just an invisible friend, like the more reticent partner who seems to take his place?
As the play takes a darker turn, are we credulous enough to imagine she was led by a rook to an axe in a field? If not, can we credit her frank confession of using that same axe to kill her parents?
What's beyond question is that the young woman is mentally unwell, showing symptoms of schizophrenia, possible agoraphobia and suicidal tendencies. Her bathroom is a retreat from the complexities of the real world: the neglect of her mother, the indifference of her father. Holding her breath beneath the warm water, she revels in her privacy and sense of control. And the bath would make such a welcome receptacle for her gushing blood.
But by casting so much doubt over the veracity of Cassandra's rambling anecdotes, playwright Gary Young seems to make a nonsense of his own story. If the young woman is a fantasist, it would be good to know where fact meets fiction. If she has a more serious mental disorder, it's hard not to feel we haven't heard it all before.
But if the script is frustrating, there's considerable visual appeal in Mark Murphy's production for Boilerhouse. Performed with little-girl-lost naivety by Melanie Wilson, the hour-long show is a constant dance of movement and colour. The promised deluge amounts only to a passing shower, and the bathroom metaphor fails to resonate - but Murphy's immersion in the play creates the momentary illusion of depth.
· At the Ryan Centre, Stranraer, tomorrow. Box office: 01776 703535. Then touring.