I grab on and haul myself up, clenching my teeth at the pain that burns in my shoulder. My foot finds the tiniest toehold, my toes clench with everything I’ve got.

‘Where next?’ I yell, eyes and hands searching for the next handhold.

‘Fassst, Cholliemurrum!!’ He leans out dangerously from the ledge to show me.

I reach for it, inch higher, but I’m not quick enough. The wolves are nearly here. I can hear their scrabbling feet, their guttural growls, their panting breath.

‘Look me!’ shouts Harby. ‘Fast! Fast!’

I look up. He’s extending his arm down to me, shaking his hand like he wants me to take it.

‘I can’t! I just can’t!’ I’m glued to the spot; I don’t dare move.

There’s a soft thud behind me as the first wolf jumps into the cavern.

I hear the clicking sound of claws on stone. I see the fear on Harby’s face. The wolf is running at me and I’m not high enough, not at all.

‘Jump, Cholliemurrum!’

My eyes lock on to Harby’s. I let go of the rock and I jump and I reach and I grasp his outstretched hand. He grabs my wrist. My feet swing out and the wolf leaps up. Reflexively I bring my knees up and they bash painfully into the wall. In a frenzy of snarls, the wolf leaps again.

But Harby’s got me; locking my eyes with his, he yells as he heaves me up on to his ledge. The wolf snaps the air and falls back to the cave floor. I lie on my stomach on the narrow ledge. Harby prods me with his foot to get up but I must be in shock because I can’t seem to make my limbs move. I peep over the edge: below, the wolf gives up on me and just stands there watching. The rest of the pack has swarmed into the cavern. They nip and scuffle and play-fight. One or two of them sniff at the mewling pups.

‘We go, Cholliemurrum,’ says Harby, and he helps me stand.

Wordlessly, he guides me upwards. The going gets easier up here and he seems to know exactly where to put his hands and feet. At last we crawl out through the opening and into the calm of the sunny afternoon air.

Harby takes his spear from his mouth, coughing. We roll away from the hole and lie, panting, on the rain-damp moss. Each breath hurts; each heartbeat hurts.

Beneath us, down in the cavern, the wolf howls; the sound spirals and loops out of the darkness, a howl so mournful I feel goose pimples rise across my whole body. Then the wolf falls silent. Utterly silent. Like he’s listening.

Somewhere down there another wolf howls. Then a third howl wraps itself around the others, then another and another. Just below us, a wolf pup howls for the very first time, his thin warble mingling with the song of the pack. The first wolf howls again, leading them all. Then, as gradually as the wolves’ song rose, it slowly fades away. The wolf pup’s voice is the last, like he hasn’t yet learned when the song’s finished.