She looked up Sir Thomas Tresham the elder and discovered that he had been the grandfather of the younger Sir Thomas and had clearly inculcated his grandson with his strong Catholic beliefs. Sir Thomas the younger’s buildings at Rushden and Lyveden all included allegories with religious significance, often based on the number three in an echo of his name “tres” for Tresham and the Holy Trinity. She wondered whether there had been any religious significance built into the garden at Knightstone. That might be worth talking to Finn about.

The thing that interested her the most, however, was the reference to the hollow hills. She wondered if this was a chalk cave somewhere near the village. She hadn’t heard any mention of a place like it and surely if it had been beneath the monastic buildings—and now the pub—someone would have known about it. She made another mental note to ask Finn.

By now Lucy’s eyes were tired from poring over the books and her screen and she suddenly realized how dark the room had become. A second later, she heard the first distant rumble of thunder and the patter of raindrops on the glass roof of the barn. She hurried to close the French windows. A hot wind was gusting up the valley, shaking the leaves and sending a couple of the patio pots tumbling over. Lucy wondered whether Finn and Johnny had managed to get all their work safely covered.

It was six o’clock and she had no idea where the time had gone. Her head still full of knights and old legends, she made herself an avocado and feta salad and ate it looking out on the valley as the storm edged closer. Sitting up here on the flat ledge above the tumbling stream felt exposed at a time like this when nature was running wild and yet it seemed to be taking the storm forever to gather its strength and burst overhead. She’d never liked storms at the best of times; there was something about the primitive power of them that made her feel vulnerable. As a child she’d seen a neighbor’s house catch fire from a lightning strike and had never forgotten it. Being in a glass house at a time like this suddenly felt far too exposed, just as it had done when she and Cleo had been alone on the night the intruder had been on the loose.

She made herself a cup of tea and curled up on the sofa with a magazine, preparing to sit out the storm. It was either that or go upstairs and get under the bed covers. She didn’t understand why she was feeling so jumpy, but there was some sort of current in the air. Perhaps it was electricity from the storm, but it felt more like the wired feeling she had had when she’d first come to Gunpowder Barn and seen Catherine’s ghost. She shuddered. How could she be cold when the night was so humid? Yet she felt shivery and afraid.