This story spans a week in the life of a couple approaching their 45th wedding anniversary. As Kate (Geraldine James) manages the preparations, Geoff (Gabriel Byrne) receives a letter about a formative ex-girlfriend who died falling into a crevasse on the Swiss Alps more than 50 years ago. Katya’s body has been found, preserved in ice. “She’s still there,” he says, and this frozen piece of his past threatens to cast the couple’s Norfolk village life together in a different, perhaps lesser, light.

David Constantine’s short story turned film is a quiet and delicate thing. So much of its emotion happens in the unspoken moments and silent revelations. What a tricky business to transpose this to the stage, so it is impressive that Hannah Patterson adapts with such spare, evocative economy.

It is a treat to see Byrne on stage too, even when he stutters or stalls over his lines. He makes a more irascible and intense Geoff than Tom Courtenay from Andrew Haigh’s 2015 film. James gives a more contained and quizzical performance as Kate but there is resonance, not least because she played the part of Kate’s friend Lena in the film. Here, in Gillian Bevan’s hands, she is more of a grating sitcom sidekick than James’s imperious Lena was.

Director Prasanna Puwanarajah infuses this understated, rather domestic story with theatricality. It is staged in a living room with a single dresser and two chairs, but becomes more symbolic and surreal, artfully turning into the loft in which Geoff has stashed the memories, and images, of Katya.

There are short scenes from across their week, tied together with blackouts and bursts of music, like a midlife version of Constellations. Beth Duke’s sound design holds much of the emotional drama with songs from this couple’s past, for dewy reminiscence; more stinging is the sound of the strong, lonely wind that evokes the Alpine mountain on which Katya perished but also the growing desolation, and danger, that Kate feels in her marriage.

It amounts to a lovely theatrical chamber piece with a gem-like delicacy. It does not quite develop in its emotional devastation but intrigues and makes you think about the passing of youth, the secrets and illusions in a long-term marriage but also the love that is here, real and solid, versus the memory of a former (greater?) love that is forever young, forever dead.