Patience, Finborough Theatre, London

So where did it all go wrong?

Suppose your life suddenly fell apart. Would you be able to think back and pinpoint a moment when it all started to go wrong; and, if so, would that help you to patch things up? This somewhat naive notion becomes an obsession for Reuben, the middle-aged hero of Patience, a ruefully funny, dark comedy by the Canadian dramatist Jason Sherman. Thought-provoking and cunningly constructed, the play wonders whether there is a meaningful causal pattern to existence or just a randomness that would drive us mad if we did not superimpose some sense of form upon it.

Suppose your life suddenly fell apart. Would you be able to think back and pinpoint a moment when it all started to go wrong; and, if so, would that help you to patch things up? This somewhat naive notion becomes an obsession for Reuben, the middle-aged hero of Patience, a ruefully funny, dark comedy by the Canadian dramatist Jason Sherman. Thought-provoking and cunningly constructed, the play wonders whether there is a meaningful causal pattern to existence or just a randomness that would drive us mad if we did not superimpose some sense of form upon it.

Reuben, sympathetically played by Geoffrey Towers in a performance that brings out his hollowness and his humanity, is the chief executive of a mobile-phone company that's on the brink of signing a big deal with Korea. He's the kind of guy who'd rather spend an evening playing squash and having a beer with a colleague than going home to his family. In a Chinese restaurant, he has an unsettling chance encounter with an old friend, Paul (Russell Bentley), whom he hasn't seen for a decade. On his way to a new career in the movie industry, Paul poses perplexingly subversive questions, as though wanting to undermine Reuben's professed content in a life of routine and increasing marital happiness. "You have everything you need, but do you need everything you have?" asks this figure, who is apparently working on a screenplay about a man who loses everything.

Reuben has good reason to brood on this meeting. Not only does he later discover that Paul died a year ago in an air crash, but directly afterwards, his own world starts to unravel. In swift succession, he is kicked out by his wife (who has found some old love letters from an abortive extramarital fling), is given the boot by his company and just misses the chance to make amends with an estranged sibling. The title of the play presumably alludes to the patience of Job, which is a neat irony, for Reuben is not in the least uncomplaining, and his sufferings are largely self-inflicted.

The drama keeps returning to the scene of an arguably fateful party 10 years earlier, where he relinquished the possibility of a love affair with Paul's wife, Sarah (Sandy Walsh). But would his life have been better if it hadn't taken that wrong turning? The tragicomic mess he makes of a second chance with Sarah now suggests otherwise.

Meanwhile, his physicist brother, Phil (amusingly portrayed by Chris Andrew Mellon), isn't much of an advertisement for the philosophy, which pointedly contrasts with Reuben's emotional determinism, of embracing uncertainty. His supposedly ecstatic relationship with a teenage prodigy looks to be about as much of a joy as a punishing fitness routine.

The play's structural intricacies are skillfully handled in Adam Barnard's engaging production. Philosophically agnostic, the drama ends with Paul's speech at the bygone party about how we are "particles illuminated by dust and light" and should simply relish the fact that we are here at all. It would sound uplifting, if it weren't for the fact this oration is an emotionally blackmailing attempt to prolong a bad marriage.

To 29 January (020-7373 3842)