Aleks and the other students left. Will and I looked at graphs of brain activity on a screen.

“So, I gather you found the Moon Stones?” said Michelle, as she searched through files on one of the computers. “Did you like them?”

“Yes,” I said stupidly, not knowing what else to say.

She gave me a sharp look that suggested she would have liked to scroll through the memory files in my brain. “You two have shown the best action from the beginning, but this morning… Look.” She clicked to a different window that was alive with brightly coloured squiggles. “You’d think that was one pattern, but it’s actually both of you, in perfect tandem.”

Patterns, I’d been bleating something about them during my fit of hysteria in the passageway.

Michelle was still speaking. “See, here are Simone and Aleks.” She pointed to an almost empty chart.

“They’re flat-lining,” said Will, with a small laugh.

“Not quite,” said Michelle. “But you see the difference. I don’t know what you two have been doing, but whatever it is…” She smiled. “Keep it up.”

She kept up the excited chat in the elevator, feverishly fingering a gold chain at her neck, as we all headed to lunch. “The research was not presented properly to you at the very start. That was a mistake. I should have spoken to you all back then, instead of just leaving Aleks to take over.”

Sitting down with our classmates in the great hall, Will announced: “We’re geniuses. You lot are dim as sheep.”

“Maybe she got the graph upside down?” suggested Justin.

Will bent close and whispered, so the others couldn’t hear. “That was quite a thing in the stones this morning.”

“It was.” I paused to think, and recalled the irresistible desire to remove all my clothes. “Oh no,” I said, also keeping my voice low. “Do you think it’s some sort of mental compulsion I’ve developed because of the stress of coming here? Am I going to be stripping off everywhere now?” Panic started to rise.

“No,” said Will. “I felt it too, remember? The need to dance, and then, once you said it, the need to feel the sun…”

“On your skin.”

He nodded. “D’you think that’s what’s caused the brain thing? What happened up there?”

I glanced over at Michelle who was talking animatedly to Aleks and Paul at the staff table.

“I honestly don’t know.”

The come-down from the brightness of the morning was deep. Life was flat, and the sun had gone in. Sun, the person, was determined that we were all going up to the circle after lunch, Saturday afternoons being free and all our own. Will, I, Justin and Ruaridh accompanied her. Holly came too, having made sure we were all scarved and gloved to within an inch of being able to breath, Justin having told her that with a Southern English mother and a Mauritian father, he was not made for the cold.

Sun talked on and on: the circle was brimming with feminine energy, and we had obviously been meant to find it. She proclaimed the flat stone to be a power centre and pointed out faint carvings, a twisted knot of circles and lines. It was interesting, but the reverential magic of the morning had gone. The sky beyond the field darkened, suggestive of more snow on the way.

Will and I sat back to back on the flat stone – it felt like our stone – and Justin took a photo of us with his phone.

“Nice one, Bevan,” said Will. “Take one with mine too, would you? Could do with a new profile pic.”

I wondered where Aleks was, and what he was doing, as many picture-taking clicks took place around us. Ruaridh had an impressive camera, and everyone’s online profiles became prehistoric as large soft flakes started to fall.

The rest of the day crawled.

Aleks didn’t look our way at dinner. He sat at the staff table and said the odd word to Paul. Simone chatted with Sadie at the student table.

Will and I sat in front of the television in the evening; Justin joined us, moaning about Saturday nights in the country.

We took the stairs to bed. Will went into his room, then Justin into his. I was left alone to climb the echoey stairway to the top of the tower.

Aleks’s door was open, and he smiled his golden smile. Simone had her back to me, hand on hip, but I could tell that she was smiling too. I saw the swell of her cheek and heard her tinkling laugh.

Aleks caught sight of me, and I fled back down the stairs.

Justin opened his door, his arms and his pyjama drawer to me, and I held his hand in the dark.