A gust of chilly winter air blows in from the living room: there’s a thudding rattle as Mhari bails out of the front window. She’s obviously had second thoughts about being trapped in the middle of a domestic argument between the Eater of Souls and a blood-cursed instrument. (Hopefully she’s taken all her stuff.)

The scroll at the end of the violin turns towards me, dragging Mo’s hands with it.

“Stop,” I repeat in Old Enochian, looking Mo in the eyes.

The pale red glow begins to fade from them, but the violin still quivers, hungry for blood. I close my eyes and look at it with my inner vision. Now I can see it for what it is: a ghastly, filthy, cursed thing, a vampire of the second order. Exactly the thing Basil warned us about. Why couldn’t it be a blancmange? I could eat a blancmange. But then I’d inherit the curse . . . a part of me is babbling inanely.

“You’re hurting me,” she says, distantly.

“I’m sorry.” I relax my grip on her elbow, but I don’t let go. I don’t want to give the violin a chance to take over again.

“Did you have sex with her?” she asks.

“No.”

Her fingers, nerveless, release the bow. It clatters to the floor angrily, but separated into its two halves the instrument can’t stop her from lowering its body. Blood trickles down its neck, across the pegbox, pooling above the scroll.

“You’re bleeding,” I say. “Let me get a towel.” She nods, and I hurry to the kitchen and grab the kitchen roll. By the time I get back she’s laid the violin on top of its open box, so similar in shape to a coffin. I tear off a couple of sheets and she wraps them around her hand. The violin is spotless already. I glare at it: it’s difficult to be sure, but I have a feeling it’s watching me the way a hungry lion watches its prey. “Kitchen,” I add.

All our most significant conversations happen in the kitchen, or over food. It seems to be one of the rules of our relationship. Another rule: don’t even think about lying. It’s difficult to slip one past someone you’ve lived with for a decade at the best of times; unbelievably harder if they’re a practitioner.

Being good at spotting lies also makes one prone to false positives: mistaking truth for falsehood. It’s the besetting curse of counter-espionage. Mo chose, for a few seconds, to believe I was telling the truth. I did not have sex with that woman. Right. But will she still believe me in the cold light of morning?

“She’s a vampire,” says Mo. She sounds almost surprised.

“So is that.” I glance towards the hall door, and she follows my eyes.

“That’s . . . different.”