“If you’re going to have guests,” the ghost said with a sigh, “would it be so hard to give me a little advance warning?” Her eyes were dark with heavy lids. She had soft cheekbones and gentle features, framed neatly by twin locks of hair, which swept her cheeks on either side. The rest was tucked behind her ears and spilled down her back and shoulders in silvery waves, like a mercurial waterfall. She had a slim, spritely figure, and her movements were as smooth as smoke in a soft breeze. She placed the cup on the tray with a gentle clink, and drifted to a seat on the windowsill. Through her opaque figure, I could see the swaying branches of a weeping willow in the yard.

“How rude of me. Jenny, this is my new assistant, Abigail Rook. Miss Rook, this is Jenny Cavanaugh. I do apologize for not formally introducing you sooner, but Miss Rook and I are currently engaged in matters of life or death, you understand.”

“I do,” she said wistfully. “More so than you, I imagine. We actually met, while you were out. Well—sort of met. I take it you didn’t tell her about me, either? Not ashamed of me, are you, Jackaby?”

“Oh bother. Of course not—other things on my mind. Did you get on well?” Jackaby’s attention had returned to the volumes on his desk, and he began absently rolling out one of the charts. Jenny’s shadowy eyes remained fixed on the window.

“We did not get on well, for your information,” Jenny said. “Nor poorly. We didn’t get on at all, because a lady doesn’t fraternize with strangers who come unannounced into her bedroom. She’s lucky I didn’t take her for a thief.” Then, with that special tone usually reserved for old, accustomed arguments, she added, “Although I wouldn’t have minded if she were a common thief. Maybe then she would have stayed across the hall and made off with some of the rubbish you’ve allowed to take over the guest room before she came traipsing into mine.”

“It’s not rubbish. I have things exactly where I like them, thank you.”

My eyes, apparently the only ones actually looking at anybody, bounced back and forth between them as they bantered as casually as neighbors over a hedge.

“Right. Because there’s no better place for my grandmother’s settee than under a dirty tarpaulin covered with crumbling rocks.”

“Runestones,” corrected Jackaby, still without bothering to look up. “I’ve told you, they’re a rare and significant record of the ancient Scandinavian gods.”

“Really? Because the last one you bothered to translate was a dirty joke about a group of rowdy drunkards.”