As the kids cleared each section, they sealed it off to make sure no grown-ups could get back in. So far they’d found twelve living ones and had killed every one of them. It had been tense and often disgusting work. The grown-ups had been living down here like animals and had collected all kinds of filth – bits of rotting flesh and bone, faeces, ragged clothing.

They’d found no sign of the two missing museum kids yet – Stacey Norman and Paul Channing. They assumed that they must have either been torn apart and their remains mixed in with the foul piles of debris in the dark corners, or they’d been dragged away and disposed of somewhere else. Whatever the case, having got rid of the living, the kids didn’t have the stomach to look too closely at the dead. As far as they were concerned, the quicker they could finish the job and make the place safe, the better.

Maxie and Blue were nearing the end of their shift. They had Big Mick and two more of Blue’s crew with them. They were all wearing face masks and rubber gloves and had spent the last half-hour scooping up the unidentifiable muck they’d found in one of the smaller rooms. The room had been lined with shelves containing fossils, but had obviously been used as a nest by the grown-ups. The kids had dumped everything they could into bin liners and were stacking them outside the door. The smell was appalling; it was so intense it was almost physical, as if someone was rubbing grubby hands over them, forcing the stench into their noses and eyes, their ears, their hair. The end was in sight, though, and they were working fast, sweat crawling across their skin beneath their clothes.

Mick and Blue were trying to shift a big, heavy cabinet. There was a crawl space behind it large enough for a person to just fit into and a hole in the wall behind leading to one of the locked rooms.

‘I reckon one of you has to go on the expedition,’ said Big Mick. ‘Ain’t no one else anyone’ll listen to. Got to be someone in charge. You should split up. One stay here, the other go on the journey.’

‘You’re probably right,’ said Blue, trying to get a grip on the chipped wood of the cabinet. ‘So, next question. Who stays and who goes?’

‘I dunno,’ said Maxie. ‘Mick seems to have all the answers. Maybe we should let him decide.’

‘Cool,’ said Mick. ‘Nobody ever asked my opinion on nothing before.’

‘That’s cos you’re a moron,’ said Blue. He stopped trying to move the cabinet and wiped sweat from his forehead.

‘You’d be nothing without me, Blue,’ said Mick. ‘You’d be lying in a dirt bed feeding the worms.’