At Ghalib’s mocking call Robert turned away from Moraima and looked towards the river. Hisham was standing on a wall along the bank.

And Ghalib had somehow climbed up onto a waterwheel. As it turned, he was climbing up from one spoke to the next, as if clambering over a treadmill. He was soaked to the skin, his red turban bright, and he was laughing. ‘Hey, Moraima - hey, God’s warrior! Look at me, look at me!’

Moraima laughed, but she clamped her hand over her mouth. ‘Allah preserve him. He’ll get himself killed.’

Robert strode towards the waterwheel, pushing through a gathering crowd of laughing onlookers. ‘Get down off there, you idiot!’

Hisham threw a mock punch at Robert. ‘You’re just jealous because Moraima’s looking at him, not you.’

Robert glared. ‘Unless you shut up she will be looking at you when I push your teeth down your throat.’

Hisham returned the challenge for one heartbeat, then backed off.

‘Hey, Christian.’ Ghalib was calling again. ‘Watch this.’ Now he was heading for the wheel’s mighty axle. He was spun around the hub, turning head-over-heels with each revolution. The wood was soaked by spray and was slippery.

Moraima ran forward. ‘Get down! Oh, get down, you fool!’

Ghalib grabbed a strut with one hand, then threw himself backwards, flinging out the other hand, so he was splayed out over the hub, turning over and over on the wheel. ‘Hey, look at me! I’m crucified! I’m Jesus on the cross!’

He actually got a laugh from the onlookers, and a smattering of applause. Hisham played up. He pulled his shirt over his head, and wailed in a loud, high voice. ‘And I’m His mother the Virgin! Oh, my son, my only son, what have those awful Romans done to you?’

On the wheel, Ghalib kept grinning, but his expression was forced, and Robert saw he was tiring.

Then his right hand slipped from the wood. He dangled from his left arm, and flailed, trying to get a fresh hold with his right hand. But the wheel turned remorselessly, and he flipped over, and his left hand started to slip too. He tried desperately to grab onto something, anything.

And he pushed his right arm inside the wheel, into the machinery. Robert heard a distant crunch, like an owl chewing a mouse’s bone. Ghalib didn’t even scream. He fell down the face of the wheel, his right arm dangling like a blood-soaked rag, and splashed into the water.

The watching people just stared. The wheel turned as if Ghalib had never existed.

Robert ran over the cobbles and climbed onto the bank wall beside Hisham. There was barely any room between the wall and the turning wheel. But there was Ghalib, floating in the water, apparently unconscious. The water all around him was stained red. And soon he would be drawn into the wheel’s machinery again.