Her voice broke and she turned around and walked away, following Marcus. Albert had never seen a back as straight, or stiff. Looking round, he found Ollie looking at him.

‘Run!’

Albert turned and ran, Colby and the others close behind. Together, they dashed into the tunnel. It was remarkably short, running only a few feet, before they hit a wall with a huge crack, about three feet wide, down the centre. June and Marcus were standing there too, Marcus still with his reluctant passenger in tow.

Albert swung back on Colby. ‘Now what? We’re trapped!’

Colby gave him a scornful look. ‘No, we’re not. Through the crack. Go!’

Marcus was already climbing up swiftly; how he was managing it at all with the violently non-cooperative Theo in his custody, Albert couldn’t begin to fathom, but manage he did, making it look easy.

‘You go next, Albert,’ said June. Her voice still sounded a little shaky.

A resounding crash echoed down the tunnel. They heard a shot, then another, followed by a delighted whoop from Ollie.

Feeling a strange grief welling up inside him, Albert reached for a handhold on the wall, the way he had seen Marcus do. He couldn’t find anything. With difficulty, and some help from June, Colby and one of his companions, he clambered up, so he was gripping on to the edge of the crack.

And then it all seemed to happen at once.

He had just got his fingers through and was scrabbling around for a better hold when June let go suddenly, causing him to slip halfway back down.

‘I’m sorry,’ she said. ‘I can’t leave him.’

She pushed past Colby and the others and then she was gone, running back towards the cavern.

He heard them shouting, and then he heard the loudest sound he’d ever heard in his life. The wall, the floor and the whole tunnel shook, small rocks and pebbles raining down on them. He lost his grip and crashed back to the floor, hitting his head hard against something and sending the world into a haze of red that began fading to black. He could taste salt in his mouth.

Then there was another terrible booming sound and the tunnel shook again, so violently that it seemed about to fall apart. Something else crashed into his head, hard—so hard he could see the walls slowly moving out of focus, dimming.

And then the blackness closed in and he knew nothing more.

11

‘Mac! Mac!’

He could hear the voice, piercing through the black-grey haze all around. He could feel his arm moving without him willing it to, shaking his head, sending jarring bolts of pain shooting into his skull. Was he having a spasm?

‘Mac! Wake up, Mac!’

Slowly, blurrily, painfully, Theo’s face came into focus, bent over him, her eyes wide with concern.

‘Mac!’