‘I’d say we’d have been chased off already if he was that unhappy.’ Tim was attacking his beer and chicken drumstick with enthusiasm.

‘Chased off by whom?’ Camilla said.

‘The people who lived here used to bury a clay jar in the doorway of the house, with a written spell inside to attract a powerful spirit. Then a djinn would take up residence in the jar and protect the house from enemies.’ Tim smiled. ‘If the Sultan’s djinn was angry with you, he’d have hurled you out already, or made you choke on your lunch maybe.’

‘Or sent a mamba to strike you down with its venom,’ said Piet. ‘Like that one!’

He leapt to his feet, pointing into a dark corner. Hannah screamed as a mottled green snake slithered across the ground in front of them, its body iridescent in the patches of sunlight.

Piet gave a whoop of laughter. ‘Silly! Don’t you recognise a harmless grass snake when you see one? Some tracker you’ve turned out to be!’

Camilla looked at him severely. ‘Don’t tease your sister like that. You gave me the fright of my life too.’

‘Sorry.’ Piet still had the light of mischief in his eyes. He turned to Sarah, who was looking out at the ruined monuments and tombs, dappled by trees and flowering lianas.

‘You’re very quiet. What are you thinking?’

‘John Masefield’s poem,’ she said dreamily ‘I can’t remember the name of it, but he could have written it about this place.

‘Like bones the ruins of the cities stand,

Like skeletons and skulls with ribs and eyes

Strewn in the saltness of the desert sand,

Carved with the unread record of King’s lies.

Once they were strong with soldiers, loud with voices,

The markets clattered as the carts drove through,

Where now the jackal in the moon rejoices

And the still asp draws death along the dew.’

There was a long silence when she had finished reciting. Hannah shivered slightly.

‘I wonder what really drove them away. Why they would have left all this.’ It was Camilla who broke the spell.

‘Perhaps, in the end, life became too fraught with hardship and danger, and they simply gave up,’ Tim said.