“Watch your step,” Nikos called out, his hands in hers as he led her up the final steps of the spiraling metal staircase. Rickety and very old but intricate in every detail, she’d almost thought the stairs went on forever.

But they led here to a very old wooden panel, weathered down. Cracks between the wood flooded a chilly evening air, brushing against her like a hand that’s been encased in ice.

He ducked his head, pulling a key from his pocket to put ...