Writer Sally Lewis and director Ben Mills deserve credit for tackling the subject of sex trafficking head-on with How Is Uncle John?, a deliberately uncomfortable two-hander about the exploitation of women by men. Holly Joyce plays a mother who reflects with both warmth and bitterness on the upbringing of her daughter, Hope, played by Naomi Stafford.

Hope's naivety about men may well be something that her mother has reservations about, but there's little evidence in their opening monologues to suggest the full horror of what happens to Hope when she's lured abroad by a handsome man, only to find herself brutally and cruelly tricked into the drugged and degraded world of a trafficked woman. The title How Is Uncle John? connects the main narrative to a specific childhood trauma for Hope, but the weakness of the story is that it jumps far too easily from Hope's early issues to her awful fate, risking a loss of credibility by not adequately grounding the reasons for the failure of the mother/daughter bond to protect her.

That said, both Joyce and Stafford serve up strong and arresting performances, breathing vibrant life into two very different women who come to have painful regrets about the decisions they made in good faith. By skimping on character development, the issues play out in far too simplistic a manner to effectively land, despite the vivid sexual details explored.

With little action on stage and most of the revelation of the characters expressed through monologues, How Is Uncle John? feels more like a radio drama than a theatre piece. A bit more development is required by both writer and director to give the play the depth that the serious subject demands.

Assembly Hall, until 29 Aug (not 16), 3pm, £10--£11 (£9--£10).