We clamber over the slippery rocks at the base of the waterfall. Somewhere behind us the wolves howl, but they’re not chasing us yet.

The frozen teeth look bigger close up, the size of tree trunks. To get inside we’re going to have to squeeze between them. We find the biggest gap and Rose goes first, then Win follows. Suddenly a whistle pierces the air, and the wolves stop howling. Then the barking begins.

I glance back. The wolves are racing across the snow, heading toward us. “Hurry up!” I shout. “They’re coming!” I push my way between the icicles and stumble after Win.

“This way,” says Rose, and she starts running toward the back of the cave, which becomes a tunnel. Win and I follow.

“I seriously hope this tunnel goes somewhere!” says Win as the barking becomes louder.

Rose comes to an abrupt stop and we almost run into the back of her. The tunnel splits in three directions. The passages leading left and right look wide and flat, but the opening directly in front of us plunges down steeply. It’s more a chute than a tunnel.

Behind us we hear skittering paws. The growls and barks get louder.

“Which way shall we go?” I say.

“It doesn’t matter,” says Rose. “We can’t outrun them. It’s impossible!”

A howl fills the cave. The first wolf has pushed his head inside the cave.

“This way,” says Win, and he aims for the middle tunnel. Immediately his feet slip out from under him and he crashes to the ground. He spins around once, twice, then disappears down the chute with a wild scream.

I look back. The mouth of the Vampire is blocked by fighting furry bodies. The wolves snap and snarl, desperate to get past the teeth and each other, and get to Rose. Win’s scream trails off. I don’t have time to think about whether he’s been whisked to safety or fallen down an icy crevasse because a wolf has gotten through and is running straight toward us. The rest follow, a mass of thick fur and glittering teeth.

Rose and I have a rare moment of total agreement.

As the wolf at the front of the pack jumps forward we dive into the icy chute. We slam down and start to slide, our arms and legs tangled, our screams competing with the snarls of the wolves.