‘Yeah. Help me up.’ Maxie stuck out a hand and Mick pulled her to her feet. After a brief discussion they picked up Achilleus between them, got their shoulders under his armpits and dragged him down the corridor, his feet scraping along the floor.

They were the last. Following where the others had gone, they looped round to the back of the café and on through into the main hall where everyone else was regrouping.

It was a mess. Blue was hacking at something on the stairs; a steady stream of blood was dripping down to where fresh bodies lay at the bottom. The stink of it hung in the air, and worse.

A mutilated father was crawling across the floor towards the main doors, a trail of slime snaking out behind him. Big Mick let go of Achilleus, walked over to the father, put his foot on the back of his head and jabbed his spear down into his spine.

As Maxie lowered Achilleus down on a bench, he stirred and opened his eyes, disoriented and embarrassed. He shrugged Maxie off.

‘Leave me alone, won’t you?’ he muttered. ‘I’m all right.’

He rubbed his head, looking around at the scene of carnage.

‘You got any water, caddie?’

Paddy fished out a half-empty plastic bottle from his golf-bag and gave it to Achilleus, who drained it in one long gulp.

‘Did we win?’ he said and tossed the bottle to one side.

‘Think so,’ said Blue from halfway up the stairs. There was a shout from above and they saw Jackson returning with another bunch of kids, younger for the most part and wearing a weird variety of fancy-dress outfits. Like characters in a cheesy school play.

‘What’s going on in this place?’ said Achilleus. ‘What they all dressed up like that for?’

‘They were having a World Book Day event,’ Boggle explained, and Achilleus burst out laughing.

‘They was what?’

‘Celebrating World Book Day. They’re dressed as their favourite characters from books, I think.’

Achilleus’ loud, mocking laughter almost distracted everyone from the fact that they had missed a grown-up. A big, ugly mother, wounded but not down, had been skulking at the top of the stairs, hidden among some display cabinets. As the last of the World Book Day kids came past her, she suddenly darted out and grabbed hold of a girl carrying a thick, leather-bound book.

Most of the kids were too surprised to do anything, but Ollie had never relaxed. He was always alert, always watching, always ready, and without thinking he had fitted a steel ball in his sling, pulled it back and loosed off a shot before anyone else had reacted.