He blinked quickly, dragged his attention back to the kitchen at Springfield and tried to describe the exhibition to Willow and Sandy. ‘Monica Leaze made this painting of a child. White dress and white ribbons. Just like everyone describes Peerie Lizzie.’

‘So you think she saw the ghost too? And painted her?’ Willow leaned forward across the table and her long hair brushed his arm. He tried not to jerk his hand away.

That hadn’t been the way he’d been thinking, but he considered the idea. ‘Maybe. I suppose it’s one explanation.’

‘And Eleanor had tracked Monica down and arranged to meet her when she was coming north?’

‘I think they must have met at some point,’ he said. His mind was racing, chasing wild notions that refused to be pinned down.

‘Eleanor must have had a busy afternoon the day of the party.’ Willow sounded unconvinced. ‘Vaila Arthur turned up to tell her story into the recorder; we think Charles Hillier might have tried to catch up with her at some point, either during the day or later in the evening; and now you decide that Eleanor and Monica had a meeting too. Just in the couple of hours that her friends took to walk along the cliff path. And knowing that they could come back at any time. It would only take a sudden rain squall to send them back to the house.’

They sat for a moment in silence.

‘Maybe the party wasn’t Eleanor Longstaff’s first trip to Shetland.’ This was Sandy, nervous that he might be making a fool of himself, looking up from his mug. ‘I mean she was always travelling on business, wasn’t she? So why couldn’t she have come here? If she’d thought her husband would laugh at her for believing in Peerie Lizzie, she could have pretended she was in Brussels . . .’ he paused, struggling to think of another suitable destination, ‘. . . or New York. Their only contact would be by mobile phone and the calls could come from anywhere.’

Another silence. Now that the words were spoken, Perez thought how obvious this was.

‘Sandy Wilson, you’re a bloody genius, and when this is all over I’m going to take you out and get you pissed.’ Willow was laughing. ‘Contact the ferry terminal and the airport. Let’s see if we can track down if, and when, Eleanor arrived. She’d most likely have flown from London via Aberdeen to save time, and she’d have needed photo ID even for domestic flights, so she’d have used her own name. Then we track her movements. Who did she meet when she was here? And why have none of the buggers come forward when they heard about her death?’ She stood up.

Perez thought he’d never seen her so excited. ‘Where are you going?’

‘I’m going to Yell to track down the mysterious Monica. And you’re coming too.’