For a couple of minutes I feel like a superhuman. Legs of steel, iron lungs, running faster than any normal person ever ran, obliterating records. Where are the Olympic judges when you need them?

But then I slow. Pain sweeps through me. I stumble. The beast snarls. Writhing on the cold, hard forest floor. Sobbing. Trying to fight. I raise my head and try...

Next thing I know, I'm in the hole that leads to the cave, tugging at the crate which Dervish left there, ripping it to splinters, clambering down into the dark abyss. Part of me hesitates. Grateful to still be human, eager to reach the safety of the cave, happy to wait for Juni, but remembering Dervish's warning-this cave is dangerous, a place of evil magic. Perhaps I should...

In the cave. I'm howling, the howls echoing eerily. With an effort I make myself stop and the echoes die away. Then all I can hear is the waterfall and the super-fast beating of my over-worked heart.

How long have I been unconscious, howling, the beast thinking it had won, only for me to somehow scrap my way back and regain control? Impossible to tell but it doesn't feel like a lot of time has passed.

The dark is absolute. It scares me. The feeling of invulnerability and supremacy which drove me through the cordon of Lambs has passed. The magic's still there and so is the beast. But mostly it's just me now, human and cold, alone in the dark, thinking with horror how close I came to killing the three Lambs, hoping I didn't hurt them too much, wondering if I did the right thing by running.

I slide to the floor and huddle my knees to my chest, clasping them tight, trying to see something-anything-through the darkness. Remembering Juni's kiss with confusion and shame, wondering what prompted it, or if I just imagined the adult passion. What I definitely didn't imagine-she said she'd stand by me even if Dervish gave up. She set me free and promised to meet me here.

It's wrong. Her intentions were good, but we shouldn't be doing this. I should have stayed and took what I had coming. Let Dervish handle the situation the way he thought best. He knows more about these matters than Juni or me. I've passed a fatal point. Split from Dervish. Crossed swords with the Lambs. Made a pact with Juni that's cut me off from everybody else. What if she doesn't come? What if she changes her mind and leaves me here? What if...

A light. I start to rise, thinking it's Juni. But then I see that it's coming from the wall of the cave, close to where the waterfall flows, just to the left of the crack I created in the rock. A strange, soft light, not of natural origin. It comes from within the wall. Circular but jagged round the rim. And in the centre, forcing its way out of the rock and into shape-the girl's face I saw when Loch died.

The jaw, cheekbones and forehead bulge outwards, illuminated by the light. The face looks like a cross between rock and flesh, neither one nor the other but a splice of the two. When it's jutting out as far as it can-I can see the tips of its ears-the eyes open. A moment later the lips move.

She speaks with urgency, words tripping off her tongue. I can tell it's important-her need to communicate something vital is clear-but I can't understand what she's saying. The language isn't like any I've ever heard.

"I don't know what you're saying," I moan, shaking my head helplessly. In response she raises her voice and speaks even quicker than before-as if that will help. "I can't understand you!" I shout, losing my temper.

Then the pain hits again. The beast howls. Magic flares. I sink to my knees, moaning. The girl's voice rises. She yells, harassing me, repeating the same sharp phrases over and over. But I couldn't make sense of her words the first time and I can't make sense of them now. I want her to leave me alone.

"Stop," I groan, but she doesn't. "Stop." Firmer this time, glaring at her, letting her see the anger in my eyes. I need peace and quiet if I'm to fight the beast and drive it back into its den. Doesn't she realise how hard this is and that she's only making it harder?

No, she doesn't. Or if she does, she doesn't care. She keeps on jabbering, voice rising, words coming faster and faster. Then a pair of hands grow out of the rock and she points at me accusingly, at the cave in general, at the crack in the rock.

"Shut up," I hiss, feeling the beast scrape the inside of my skull with its claws. "I can't take anymore. Stop it. Stop it! STOP!"

With the final cry I lunge to my feet, throw my hands wide and scream.

A sharp snapping sound-the crack beside the waterfall widens and lengthens. The girl's face and hands disappear. And the waterfall freezes. It turns to ice. A solid stretch of crystal from top to bottom, glistening beautifully, caught in full motion, an image no artist could ever hope to replicate.

I stare at the ice, mesmerised. How the hell did I do that?

Then the light where the girl's face was fades. I'm plunged into darkness again. Moments later, while my head's still spinning, I notice the glow of another light behind me. I turn, expecting the face again. But this is the flickering of a torch. And it's coming from overhead, from the shaft to the forest above.

"Grubbs?" someone calls-the most welcome voice in the world.

"Juni!" I cry, stumbling towards the spot where she'll enter the cave. "Come quick. You'll never believe-"

Agony. A flash of total torment. The beast, closer to the surface than ever. Incredibly powerful. The magic flares in response. The pair wrestle, spitting flames, fighting for possession of my body and soul.

I collapse, screaming. Juni shouts my name again. The world dims around me. My thoughts go thin. I try to call and warn her to stay away. But it's too late. I go under. The beast drives me down. I vanish.

Returning to my senses. Indescribable relief. When I felt myself lose control that last time, I thought I was finished. No more Grubbs Grady. Lost forever. Werewolf in command from this night till doomsday. It's good-delicious!-to be back.

But relief fades as quickly as it swelled. I'm no longer in the cave. I'm in a house and there's blood everywhere. A couple of mauled, gutted bodies on the floor. Juni stands across from me, beaten and bruised, bleeding freely from her arms, head, neck. She's facing me, talking rapidly, hands outstretched and making frantic gestures, trying to calm me down.

I'm growling at her, my bloodstained fingers curled into fists, keeping her away from the corpses-apparently the beast wanted them all for himself.

I manage to stop growling and lower my hands.

"Grubbs?" Juni croaks nervously. "Is that you?"

"Uhrs." I cough. Clear my throat and try again. "Yes."

"Thank god," she weeps, collapsing. "I thought you were going to kill me."

"I'd never..." I stop and look around. I know this house. And now that I look past the layers of blood, I know the people.

Ma and Pa Spleen!

"No!" I cry. "Not Bill-E! Tell me I didn't-"

"Behind you," Juni says through her tears.

I turn slowly, expecting the worst, ready to rip my own heart out if I've killed my brother. But he's alive. Lying on his stomach, unconscious, bleeding from a blow to his head. But his body's moving with his breath. I go to him quickly, turn him over on to his back, make him comfortable, check that the cut to his head isn't serious.

"You changed," Juni moans. "I couldn't stop it. I thought I could tap into the magic of the cave and help. But you became a monster and tried to kill me. I managed to ward you off. Quenched the light. Hid in the darkness. Masked my smell using magic.

"Then you left. I tracked you here. You burst in before I arrived. Killed the old pair. You would have killed Billy too, but I fought and stalled you. I don't think I could have held you off much longer. If you hadn't turned back when you did..."

She breaks down. I stare at her, then at Bill-E. Then at the butchered Ma and Pa Spleen. I never liked them. They were cranky, selfish busybodies. Always interfering, trying to keep Bill-E and me apart. But they didn't deserve this-ripped to pieces in their own home by a savage animal of the night.

"What have I done?" I cry, sinking to the floor, burying my head in my hands. "I killed them. I'm a murderer."

"No," Juni sobs, crawling across, trying to prise my hands away. "It was the beast... the werewolf. You didn't do this, Grubbs. It wasn't your fault."

"Of course it was!" I scream, head shooting up. "I knew what was happening. I knew I had to be locked up, what I could do if unleashed. I should have stayed in the cage and let the Lambs slaughter me."

"Don't say that," Juni pleads.

"It's true," I cry. "I should be dead now, not the Spleens. It should be..." I stop, frowning. "But why did I come here? Why pick on them and Bill-E?"

"You didn't like them," Juni reminds me.

"But I didn't hate them. And Bill-E's my best friend. Why...?"

"Does it matter?" she interrupts sharply. "You were jealous of Billy, or you wanted to kill his grandparents, or the beast just came to somewhere it knew, to a familiar place it stole from your memories. It could have been your home, school, another friend's house. It happened to be here. What of it? Just be glad you regained consciousness before... before..." She can't continue.

I pat Juni's head as she cries. The tears have dried in my own eyes. I'm staring at the dead bodies again, but calmly, detached, knowing what must be done.

"Phone Dervish," I tell Juni. "Give him our position. Ask him to bring the Lambs. I won't fight. They can have me. I'll surrender."

"No!" Juni gasps. "They'll kill you."

"They'll exterminate me," I correct her. "And that's what I need. This can't go on. I was wrong to run. I..." A thought. "Dervish doesn't know you helped me, does he?"

She shakes her head. "I told him you broke out, that I tried to stop you but couldn't. He took off with the Lambs to track you down. I stayed behind, then sneaked out once they'd gone. He doesn't know anything."

"Good. Forget about ringing him. I'll do it. Go home and clean yourself up. Say nothing about this to him. You don't have to be involved."

"You don't know what you're saying."

"Yes I do. This has gone far enough. Too far. I killed tonight. Whether it was me or the beast doesn't matter. We both know that, if I carry on, I'll kill again. That can't happen. I won't allow it.

So go. Thanks for everything, but I'm past helping." I reach for my phone and start tapping in numbers.

Juni gently takes the phone from me. "Come away with me," she whispers. "We'll go where nobody can find us, where you can't hurt anybody."

"What are you talking about?" I frown, trying to get the phone back.

"We'll run," she hisses, holding the phone out of reach. She's stopped crying. Sounds more like her old self. I can imagine her brain whirring behind her eyes. "Head for somewhere secluded and remote. When the next full moon comes, we'll go up a mountain or into a cave. I'll tie you up and sedate you with magic and drugs to make sure you can't kill anyone. I'll only set you free when the moon has passed. We'll stay in that place and carve out new lives for ourselves. Keep the world safe from you... from the beast."

"You're fantasising," I sigh. "It wouldn't work. You saw what I did to the cage. I'd escape and kill again."

"No," she insists. "I can control you. I'm sure I can."

"And if I change forever the next time?" I ask. "If the beast takes over?"

"Then I'll do what the Lambs tried to do tonight," she vows. Takes my hands and squeezes. "Don't doubt my conviction. If I have to kill you, I will, regardless of how much that would hurt me. But I don't want to harm you if I don't have to. I still believe you can be saved. The werewolf should have taken you over tonight, but it didn't. You fought it and won. You can win again, I'm sure you can. If I'm wrong... if you lose..." Her jaw goes firm. "So be it. But we have to try. Life's too precious to throw away needlessly."

"I don't know." I look at the bodies again, at Bill-E. "The risks..."

"There'll be none," she promises, standing and pulling me up. "We'll leave immediately and find a place where you can't hurt anyone."

I hesitate, torn between knowing the right thing to do and wanting to live.

"If not for yourself," Juni says softly, "do it for me. I love you, Grubbs. Please. Stay alive. For me."

I don't know what to say. I want to go with her. But the beast... the magic... the murders. I open my mouth, meaning to ask for the phone again, making up my mind to act bravely, selflessly, for the welfare of those I care about.

But what comes out is a weak, "OK. But you have to promise to keep me away from people. And, if necessary, you'll stop me the next time, any way you can."

Juni crosses her heart and smiles. "I promise." She goes to the back door and opens it, then pushes me ahead of her, out into the night. I stumble through the doorway meekly, silently cursing myself for my cowardice, head low, crying again. Once I'm out, Juni quietly closes the door on the bloodshed and carnage, leaving Bill-E sleeping, to awaken later in the morning to horror and chaos.