There were often, I knew, in abbeys and the neighbouring houses, secret chambers and hideaways built to protect imperilled priests during the Tudor persecutions. It would not have been surprising if these “priest’s holes” were connected to the rest of the abbey by the underground passages which King Henry always claimed were employed in the canons’ secret amours.

“A priest’s hole,” I said, as the soft ticking sound repeated yet again, as the febrile gleam in my poor friend’s eyes grew brighter. “Where is it? Can we get inside? Come on, out with it, man.”

For the second time that night, Quentin cast a queerly knowing look at the door.

Tick-tick. Tick-tick. That infernal noise again. What was it?

“In the study,” Quentin said.

I did not hesitate; the slightest hesitation would have done for my resolve. I marched, with more boldness than I felt, across the room to the fireplace. I seized a candle from the mantlepiece, bent to touch the wick to an ember. When the taper ignited, I carried the flame back to where Quentin stood. His face in the wavering glow was stretched and taut with apprehension as he began to understand my intent.

“Neville,” he gasped, “we can’t, we mustn’t …”

“We will,” I said sternly. “Follow me.”

I pulled him from the window, fairly dragged him after me to the door. It was harsh therapy, but effective. As Quentin was torn from his passive terror and offered the prospect of an enterprise, a measure of his former vigour seemed to return to him. His trembling ceased, and by the time we broke from the chamber into the corridor, he was following after me of his own volition.

With every step we took, the sound grew louder, nearer. Yet always, always, it surrounded us, vibrating behind the portraits, beneath the flooring, above the beams.

Tick-tick. Tick-tick.

At my shoulder, Quentin began to protest again, his expression urgent in the trailing candlelight, his words tumbling over one another.

“Neville. Neville, listen … For God’s sake … You don’t know what you’re dealing with … You don’t understand … Listen to me … Listen, before it’s too late …”

I raced on, ignoring his admonitions, closing my mind to them lest they dissuade me from my purpose. The persistent, rhythmic tapping all around us grew yet louder, nearer. I felt as if it had entered my brain, was rapping at me from within.

Tick-tick. Tick-tick.

“Neville!” Quentin cried again.

“Is this the door?” I said, as we reached the study. Raising my candle high, I grasped the iron handle. At a nod from Quentin, I pushed it down. The door swung slowly inward.