On the steps of a stone building, a group of people were standing in front of a doorway, the men wearing stout plus-fours and the women dressed in suits and cloche hats. Underneath in a neat, old-fashioned hand was written: House party at Eilean Dobhran, 12 August 1920

‘Oh, look,’ breathed Marnie. ‘There’s the same dog as in my photo! It has to be the one the old lady used to tell me stories about! I can’t believe it.’ She ran her finger along the line of writing, almost feeling that by touching the letters she could be transported back in time. ‘How do you say the name?’ she asked.

‘It’s pronounced “ee-lan daw-ran”. In Gaelic eilean means island and dobhran means otter.’

‘The Island of the Otter,’ repeated Marnie, entranced. ‘I think your old lady was Lucy-Anne Drummond-Gray of Eilean Dobhran,’ said Evelyn, looking very pleased with herself, ‘and the red hair of the child in your locket confirms it for me. Most of that family had flaming hair and tempers to match it! It was their downfall.’

The others clustered round to look at the album but Marnie, choked with emotion, got up and walked over to the window. She stood gazing out on the azaleas and rhododendrons of Tillydrum but seeing in her mind’s eye a different garden with very different plants; hearing a voice saying: ‘Listen now while I tell you how I was once found by my dog when I got lost on the hill in the mist,’ as a lonely old woman, battling to come to terms with an overwhelming loss and her own approaching death, rocked in a hammock with a frightened little girl.

Christopher walked over to her and put his hands on her shoulders. He could feel her trembling. They stood together for a moment while she collected herself, then she put her own hand to her shoulder and just touched his hand. It was an almost imperceptible, highly personal private gesture but both Isobel and Louisa saw it before Marnie turned round to face the room again.

Isobel felt a lump in her throat and had tears in her own eyes; tears partly brought on by the pathos of old photographs with their memories of times past and reminders of future mortality, but also by pleasure for Marnie at the rewards she was reaping on her self-imposed mission – until she glanced at Louisa and saw the look of sadness on her face and was reminded again that Louisa’s quest, whatever it might be, was not proving so fulfilling.

‘I don’t know how to thank you,’ said Marnie. ‘You can have no idea what this means to me. There’s so much more I want to ask – will you tell me all you know?’