Music means everything to Catriona and Umberto in Concerto; it is a world they share, one they both know by heart; wordlessly, they speak the same language. So they both appreciate the dramatic, stirring music of a storm.

They are young when they first come together for a night of passion. The next morning, they awaken to storm clouds:

Catriona leapt out of bed and ran to the window. Day was almost breaking and the stars were fading in the morning pallor. Angry thunderclouds rolled their rainy pillows in fantastic forms, continually torn, scattered and reunited by the driving wind. She watched them march across the firmament like an avenging army. The battle opened. Thunder rumbled in the distance and crashed, and the zigzag of a vivid firebolt turned the wan light into a riotous jazz that mocked the solitude of the endless sea and pried into the secret places of the earth.

Catriona is not frightened; she loves a storm, always has – she finds them exhilarating, bewitching. Umberto is delighted that she too appreciates nature’s spectacular show. ‘Come and watch with me,’ he says. ‘Nature’s orchestra is playing Wagner’s “Ride of the Valkyries” for us.’

The storm brings the two together, and they make love for the first time. But after the storm, when all is calm, their affair is over: Umberto receives a call from his agent with an offer to tour America, and he chooses his career over Catriona.

Years pass, and Catriona has moved on with her life, raising her son as a single mother and working as a music therapist. She has built a safe life where her heart is protected – no man will hurt her again. But then Umberto’s mother contacts Catriona and asks her to take Umberto on as a client; he has lost his sight and spiralled into depression.

As she considers this offer of work, Catriona finds emotions rising within her. Umberto left her – and though he did not know it, he left her pregnant with his child. She knows deep down she owes it to her son, Michael, and to Umberto to be honest. But she is fearful to go to Umberto now; scared of getting hurt all over again.

A storm is brewing outside. Catriona steps out into the garden:

 She looked up at a sky hung with stormclouds, its pale moon partly obscured; very like the one on that fateful night with Umberto in Villefranche, she thought to herself as she stepped off the lawn at the back of the house into the grass of the orchard. A chill wind was blowing from the highest peaks of the Alps behind Nice, making a dismal rustle among the fruit trees. She never heard such fatal murmurs nor had she ever felt herself in such a gloomy cast of mind – even after Umberto had left her, even after she had discovered that she was carrying his child. …

When the storm broke and great drops of rain came cascading down, Catriona returned to the lawn, where she stood under the rain, her face lifted to the sky. She welcomed the feeling of the fresh water drenching her as she watched the fantastic forms of thick clouds continually torn, scattered and reunited by the wind. They looked as if they had been painted by a heavenly brush – shaded dark lower down, lighter above, and illuminated dramatically when lightning flashed through them.

For Catriona, the storm is cathartic, playing out all the difficult emotions she feels. Standing in the rain, she feels some of these emotions wash away; she is cleansed by the storm.

But then, as quickly as it came, the storm is gone. I write:

The night sky brightened and then, suddenly, a very pale gleam of yellow light appeared opposite the moon. How extraordinary, Catriona marvelled. It must be a moon bow! She had read about lunar rainbows, caused by the moon’s light refracted off water droplets in much fainter colours than those created by the sun. In local superstition they were considered a good omen, she remembered…

She will go to Umberto, at Lake Como. She will try to help him, as a client. And somehow she will find the strength to tell him he is a father.

But how will Umberto react? Is he still the same man who revels in a storm? After all, he lost his vision in one:

It was a stormy night, with a fierce blizzard coming down from the Alps, and he had been angrily rehashing the conversation with his mother as he drove down the motorway. He was too late to miss the lorry that seemed to come out of nowhere as it overtook him, bumping his car off the road and sending it rolling into a ditch. All he remembered was spinning, twisted metal, shattering glass. Then blackness … and waking up to the horrifying blackness that had never left him since.

In fact, Umberto lost a great deal more than his vision in that storm. He lost his hope, his faith; he lost himself. But as Vincent van Gogh wrote, ‘There is peace even in the storm.’ Can Catriona help Umberto to find that peace? Can the two stand together once more and look out at a storm feeling exhilarated and inspired – can they stand out in it, embrace it, dance to nature’s symphony?