The rain came down in silver sheets, and Ria was utterly lost. Her phone had died hours ago, the map on its screen fading into blackness just as the first drops began to fall. The narrow, cobbled street she’d turned down in a panic was more of an alley, lined with impossibly high, ivy-choked walls. At the end of it, a single structure loomed, a gothic mansion of dark stone and piercing spires that seemed to swallow the weak moonlight.

A tall, iron-wrought gate stood ajar, as if expecting her. With a shiver that had little to do with the cold, she pushed it open. The groan of the hinges...