Michael Richard and Jackie Rens as Oliver Lucas and Nadia Blye, in the Vertical Hour. Photograph courtesy Montecasino Theatre.

Life changing seduction can happen without either party laying a finger on the other. This is the underlying erotic edge, in The Vertical Hour, a David Hare play about choices.

Phillip Lucas (Richard Gau), a young physiotherapist based in America is taking his girlfriend, Nadia Blye (Jackie Rens) to meet his estranged father, Oliver Lucas (Michael Richard), a once sought after nephrologist, in Wales. It is in the immediate wake of America’s war on Iraq. Nadia is a foreign correspondent in warzones turned professor of political studies at Yale University. She’s a hard-edged young woman with a profound sense of definiteness about her.

The visit serves to unhinge several ghosts in the lives of the Lucas father and son and while the Vertical Hour refers to a moment in combat, after a disaster, after a shooting, when you can actually be of some use, it is exploited in a number of different combative directions, from the lecture theatre to the father and son dyad, the piece is fraught with dynamic tension.

Unfortunately, Gau’s lack of gravitas and too tender years cause the piece to buckle. He’s just not convincing as the kind of man that would be capable of seducing someone like Rens’ character.  She, in turn embraces Nadia Blye with a real sense of authority, perhaps too much: the hard-as-nails persona is mind-numbing and all embracing and the character loses dimension and lacks heart. The work is held together by Richard’s demure and almost sinister maturity as the ageing doctor who lives alone in a gorgeous place.

He reads through the young politics professor as though she were a comic, gutting her emotionally but with devastating quietness, within minutes of meeting her. It’s a seduction like you might never have seen before: the air becomes electric and the woman is overwhelmed with words alone. But it is not sexual. It is about power.

It’s an essay on parenting as it is one on education. Two very powerful devices of the lecturer in combat with her students bracket the play and feature newcomers Jaco van Rensburg and Sinakho Zokuta as Dennis and Terry respectively: two students who go head to head with their professor, willing to bring their personal baggage into the mix.

The Vertical Hour, with its set comprising paintings of imploding British and American flags, is a little hurt by casting decisions, but its strength of plot and Richard’s haunting presence holds it together and keeps your focus.

• The Vertical Hour is written by David Hare and directed by Fred Abrahamse. It features Richard Gau; Jackie Rens; Michael Richard; Jaco van Rensburg; and Sinakho Zokuta and performs at The Studio, Pieter Toerien Theatre, Montecasino, Fourways, until November 9.