Billed as a dynamic legal thriller, Conflict of Interest turns out to be something rather different, and not always in a good way.

The setting is Philadelphia in the 1980s, where Arthur Carmichael (Thomas Carruthers) and Mitchell Hargrieve (William Leggetter) run a successful criminal defence practice. Alongside them is Talia (Amy Cash), the firm's young intern. Their routine is interrupted when Rita Lempkin (Rhian Holmes) walks in asking for help after the murder of her wealthy husband. The case sounds uncomfortably familiar to Arthur, who once defended a woman named Lucy, accused of killing her own father. They fell in love and married, and Lucy Carmichael (Maeve-Anne Allen) is now very much part of his life. As the new case echoes the old one, the cracks begin to show within the firm.

The best thing about the evening is the cast. All five actors give committed, convincing performances, and they do their best with material that rarely gives them room to breathe. Carruthers and Leggetter hold the stage with real conviction, while Cash, Holmes and Allen make the most of their scenes. There is genuine talent on show here, and it deserves a stronger script.

But if you come expecting a pacy courtroom thriller, you will be disappointed. The characters talk, and talk, and talk, about their lives, their troubled families and their various private miseries, from the opening scene right through to the end. The first act in particular drags badly, and I spent much of it wondering where all these storylines were heading and what any of them had to do with the murder at the centre of the play. The tension that a title like this promises never really arrives, and the legal drama is buried under backstory. Even when the plot does finally spring into life, it offers little in the way of surprise. The two twists, if they can be called that, were clear to me long before they arrived, so the supposed reveals landed with a shrug rather than a gasp.

It doesn't help that the two male leads are thoroughly unpleasant company. Arthur and Mitchell are unhappy, bitter and misogynistic, and spending the best part of two hours with them is wearing rather than revealing. It's one thing to write flawed men, but another to give us no reason to care what happens to them.

A strong cast, then, but a play that mistakes talkiness for depth and never delivers the thriller it advertises.