Dr. Wills’s office is surprisingly spacious. It’s what we jokingly refer to as an Ark Special in the Laundry: it’s actually sized for two people, with two desks, two workstations, two of everything. I take the visitor’s seat across from her—one that is clearly accustomed to regular visitors, for it is free of clutter and situated in a clear patch of floor. She shuts the door behind us: I appreciate the gesture. “What can I do for the Laundry today?” she asks.

I take a deep breath. “You’ve worked with us before, I gather. On K syndrome.”

“Krantzberg-Gödel Spongiform Encephalopathy. Yes?” She waits for me to nod.

“That’s it. Um. Tell me, for epidemiological purposes, speaking hypothetically”—I’m making a hash of this; I force myself to get a grip—“suppose there was a significant outbreak of K syndrome in the UK, am I right in thinking that the first thing we’d know about it would be a spike in cases of CJD being diagnosed by post-mortem examination?”

“If there was a—” Her expression could not be more eloquent if I’d asked her how we’d know if there was a minor outbreak of the Black Death: a mixture of pungent disbelief, the barnyard stench of second-guessery, and a high note of oh shit all colliding simultaneously in the back of her mind. It’s enough to freeze anyone’s tongue, so I give her a few seconds before I grin and nod, trying to look like an idiot student in need of tuition. “Please tell me you’re joking? No? Oh fuck.” She slumps back in her chair. “Hang on.” She straightens up again as second, and then third, thoughts line up in a disorderly queue. “This isn’t a joke, is it?”

“I sincerely hope not. I don’t want to waste your time or mine. Look, I know you’d be aware of actual referrals for treatment, patients with active disease and a diagnosis, right?”

“Yes, that’s exactly right! So there can’t be an epidemic without us knowing about it, because—” She stops dead.

“Because it’s a progressive disease, and you’d be seeing them as referrals from wherever they were diagnosed?”

“Yes.” She frowns, perplexed. “Your scenario doesn’t make sense, I’m afraid.”

“Okay. Let me try again. If coroners around the country began recording spongiform lesions in the brains of patients who had died suddenly in the past month, how long would it take you to hear about it?”