“There used to be a curfew and we, being the dreadful young men that we were, wanted to go out drinking,” he said. “It’s not easy to beat a curfew when the masters can command the very spirits of the earth and air against you.”

“Really?” I asked. “The spirits of the earth and air?”

“So they said,” said Nightingale. “And I for one believed them.”

“So no drinking,” I said.

Nightingale made a werelight and stepped through the door. Not to be outdone I made my own light and followed him inside. I heard Toby barking from outside but he seemed reluctant to follow us in. Our werelights illuminated a short corridor of undressed brick that reminded me of the service corridors under the Folly.

“Not until you were in the sixth form,” he said. “Once you were inducted into the common room, the upper six would teach you the spell for the night gate and then you could go drinking. Unless you were Horace Greenway, who was unpopular with the prefects.”

We reached a T-junction and went right.

“What happened to him?”

“Died during the battle of Crete,” said Nightingale.

“I meant how did he get to the pub?”

“One of us would open the door for him,” said Nightingale.

“And the teachers never twigged you were sneaking out?” I asked.

We reached a flight of wooden stairs leading up. They creaked alarmingly under our weight.

“The masters knew all about it,” said Nightingale. “After all, they’d once been sixth formers themselves.”

As we reached a short, wood-paneled landing I caught a flash of vestigia, lemon drops and sherbet, wet wool and the sound of running feet. I saw there were brass coat hangers lining both walls and benches sized for adolescent boys to sit and change their shoes. I brushed my fingertips on the wood and felt instead the rough paper of old comic books.

“Plenty of memories,” said Nightingale when he saw me pause.

Ghosts, I was thinking, memories—I wasn’t sure there was a difference.

Nightingale opened a battered wooden door and we stepped out into a huge hall, the suddenly inadequate werelights revealing two massive staircases and bare stone walls that still showed faded rectangles where framed paintings had once hung. With all the windows covered, we’d have been in pitch darkness if we weren’t making our own lights.

“The great hall,” said Nightingale. “The library’s up the sinister staircase.”