We reached the limestone in the middle of the day. Both the doctor and the master had been able to complete their circuits in the time it took us merely to get up there. They were waiting at the entrance to a large cave. Argyle sat in silent contemplation, looking out over the blue expanse of the sea stretching eastwards, back towards Great Island. His soft cotton dress was damp with sweat where it gathered over his chest, and thousands of tiny grass seeds decorated the skirts as though the dressmaker had intended them to be there. He picked at them idly.

Up here, the wind had enough force to moan through the fissures in the rock and swirl my hair in strands about my face. I wished I had tied it: it was more than my fingers could control. The cave faced south-east and stretched back far enough to give shade from the midday sun as it receded into darkness. The f loor was evenly worn, scraped f lat and soft by wallabies. The badgers, too, had left their distinctive square droppings.

My father laid himself on the soft floor and began to shiver, despite the heat.

The doctor beckoned me further in. ‘Feel the difference in the air,’ he said, quietly. ‘It muffles sound.’ My eyes adjusted to the gloom as I walked further in with him. Now I looked back to the entrance and it appeared as a jagged tear, incandescent against the fabric of the dark earth.

‘People have lived here,’ the doctor went on, speaking quietly to himself. ‘Very old, profoundly old.’ He examined the walls as he strode deeper in, his fingers tracing irregularities in the surface. ‘But not for a long time.’ Now both his hands were pressed flat on the surface of the rock and he held one cheek to it, exhaling softly.

I was walking with him, deeper in. I should not have been.

There was a narrow cleft at the bottom of the cave’s rear wall. He bent down and peered in, muttering into the darkness.

‘How would they have got here?’ My question broke his reverie.

‘Oh, sea, perhaps. Or, the sea was lower—these islands were mountains once and one only had to walk over the plains to reach them. Divine punishments, you see. Or merely the slow change of the earth. Oceans come and go. Mountains too.’

He turned to me and his face was half-lit by the glow from the cave’s entrance. The other half, in shadow, rendered him in a new and unsettling expression. He was serene, staring into my eyes and yet not seeing me.

Without taking his eyes from mine, he said, very softly: ‘Your father suffers quart mania. It is the illness that attends the withdrawal from liquor.’

I didn’t understand. He was often sickly after a binge, but what I had seen that morning, what the doctor was referring to, was something different. A low moan came from the entrance where I had left him, and I suddenly felt the need to rush towards him, away from this man who was a stranger all over again.