Faith Healer at the Donmar Warehouse. Photo: Johan Persson.

Behind a rippling curtain of rain – itself drenched in silver light – a performance is about to take place. The Fantastic Frank Hardy, Faith Healer, is in town to attempt miracles, and in this charged atmosphere the miraculous already seems possible.

It’s not just that the indoor downpour matches the biblical rain most of the UK has been experiencing lately. There’s something transporting and hypnotic about it, a perfect tonal match to the slow, steady, and insistent power of Lyndsey Turner’s production.

Although its first run in 1979 managed only a scant 20 performances, Faith Healer endures as one of Brian Friel’s most satisfying plays. A subtle, insinuating masterpiece of direct address, it presents three characters through four overlapping – often conflicting – monologues, exploring memory, truth, and innocence. Innocence as a capacity for hope. Innocence, as a finite ability to maintain illusions. As the narrative unfolds and the audience draw their own conclusions from the puzzle of corroborations and contradictions, each character gives their account of events, and ends up with all those illusions stripped away.

There’s the act’s promoter Teddy (Ron Cook), a 100-words- per- minute cockney raconteur with a wealth of showbiz anecdotes and an unspoken yearning for a life wasted and a life never lived.

There’s Frank himself, played by a quietly charismatic Stephen Dillane. All ruffled charm and soft-spoken eloquence, he’s composed of equal parts self-doubt – for the nine times out of ten when nothing happens – and uncomfortable awe at the rare occasions when something does. One time, he tells us, he cured ten people in a single night. He’s been carrying around the newspaper clipping that mentions it for years, like a talisman.

If Frank is driven by his need to prove himself, his wife Grace is motivated by a complicated and unhappy love. Gina McKee brings a beautifully-judged insecurity to the role, with flashes of grief and anger spilling over as she refutes the other’s depictions of her as either uncomplicatedly loyal or viciously co-dependent. When she sighs, towards the end of her scene ‘I’m such a mess,’ it’s an instance of absolute honesty which unravels the skein of half-truths and misremembered moments we’ve been presented with.

By the time we return to Frank’s perspective for the final monologue, the cracks in his confident façade have widened to chasms, and the vulnerability which seeps from him has become horribly poignant.

Designer Es Devlin stages it all on simple sets which each neatly reflect something essential in the characters. A few stacked chairs represent a procession of indistinguishable town halls. A basket of laundry in a shabby bedsit. A box of ratty memorabilia. As with every aspect of this production, the audience is asked to fill in the blanks, to believe an account, or focus on a detail, or disregard it.

The question of whether Francis has a special gift or is merely a charlatan, whether he’s a conman or a deluded braggart is never answered. There’s no need for it to be. It’s just another texture in a complex and pensive character piece. Woven through all the monologues, there’s a mantra-like repetition of the names of impoverished towns they’ve toured to. As the story unfolds, one name becomes more frequent – the site of a terribly personal loss. There’s a sense of inevitability, of fate, drawing all these misaligned threads together. The play’s last moments are filled with awful, focused tension, the payoff after all that slow-burn character-building.

Dour and downbeat it may be, but this show has all the cumulative power and electric charge of a gathering thunderhead.

Faith Healer is on until 20th August 2016. Click here for more information.