With a jab of his keyboard the map was replaced by an aerial view of the same area. It was a modern photograph. The parched yellow paper had been bland as desert sand, but now all details were defined in full colour. Its angle and range from the earth had been altered to mimic the original map, so the photograph was still skewed to Ben’s eyes.

‘Now then,’ Sparling continued, ‘here again we see the same village. This image was captured only a few months ago. Almost two hundred years have passed and practically nothing has changed. Two hundred years,’ he repeated. ‘A number of new homes have been built. But that is, of course, to be expected. Free from disease and hardship, families inevitably grow. All original buildings are still intact, Ms Coogan. Even the outhouses and stables are as they were.’

Ben noticed Chloe shifting in her seat. It would have seemed that Sparling had caught Ms Coogan’s attention. Some people were more easily excited by outhouses than others.

‘This aerial photograph and the original map have another common trait,’ the doctor added. ‘There is one key element missing from both. Can either of you identify what that might be?’

Ben sat forward to scan the details. Was this a test? Sparling had recruited him because of his knack for charming stories out of the elderly. He had a map of Ireland in his thesis but that was no more than filler – a means to fatten up the page count; tricks of the trade for any budding academic. His was a layman’s eye when it came to cartography. Still, he frowned at the map as though suddenly enlightened by a hundred fantastic theories as to what Sparling wanted from him.

‘There’s no road,’ Chloe said simply.

‘Precisely, Ms Coogan,’ Sparling replied. ‘Tír Mallacht was a curiously insular community, even by Irish standards, and still is to this day. Accessible only by foot, it is in essence a time capsule. One unaffected by the world around it.’

‘You mean to tell me,’ Chloe said, ‘that the same families have lived in that little village for nearly two hundred years?’

The door atop the stairs was heard to slightly open, like an airlock, and close back into its frame. Ben turned in his seat at the sound of it but there was no one there. It could have been a draught. Or some caretaker who hadn’t realised the hall was occupied until they heard Chloe’s voice. Either way, Sparling’s body stiffened. He stared at the door, waiting longer than seemed necessary.

‘That is correct, Ms Coogan,’ he eventually replied.

‘So, their gene pool is…’

‘Most limited.’

‘But why have they never left?’ she asked.

‘A fine question, Ms Coogan, and one that I would very much like answered.’