Dervish starts to question me, to find out why I'm here, how I know Beranabus. But Shark cuts in. "The attack could come at any minute. We need to prepare for it."

He pulls the doors open and gestures me inside. It's dark and incredibly noisy. The room's quite large, but packed with punks. Mostly guys, Dervish's age or a bit older. A band is playing on a small stage to our right. Thrashing away at their guitars and drum kit as though the world is about to end and they're determined to finish their song before it does. The singer screams into his microphone, mostly swear words, sticking his middle fingers up at the crowd and bellowing at them.

The punks love it. They're dancing like crazy, leaping up and down or holding on to each other and spinning wildly. Some are fighting, but it's good natured. They're drawing blood, but they don't care - that just adds colour.

There are more studs, piercings and tattoos than I've ever seen. That reminds me of Shark's knuckles and I look down at his hands. His name is tattooed on both sets, a letter per finger, with a black and white shark's head filling the flesh between both thumbs and index fingers, jaws wide, teeth glistening.

"It sounds like a dentist's drill," Shark yells at Dervish, scowling at the noise. "You really like this crap?"

"It's the new wave," Dervish grins. "The music of change. An-ar-cheeeeeee!" He punches the air with his fist.

"Grow up," Shark snorts, then looks down at me. "You like this?"

"I've never heard anything like it," I tell him. "It's giving me a headache."

Shark laughs. "The kid's got more sense than you, Grady."

The song ends and the band takes a short break so that one of the guitarists can replace the guitar which he's just broken. Dervish uses the lull to fill me in.

"Somebody's summoning a demon. We've been trying to stop him for the last couple of weeks. We don't know who the summoner is, but we know the crossing's going to happen here, tonight. If we can't stop it, we plan to kill the demon or push it back."

"We won't be able to kill it," Shark says. "We're not strong enough to destroy a demon. In the Demonata's universe, maybe - but driving it back is the best we can hope for here."

"Have you done this a lot?" I ask.

"I have. This is Grady's first taste of action." He punches Dervish's arm. "I'm not sure he's up to it."

"Don't worry about me," Dervish growls. "I'll do what I have to."

"I know you will," Shark chuckles. "Now, let's try and find the demon-loving scumbag, though I guess we won't know who it is until - "

"He's over there," I interrupt, pointing at a middle-aged man near the stage. He's dressed like a punk, but doesn't really fit the part. Lean and muscular, with a thick Mohican haircut. His lips are moving steadily. He's the focus for the patches of light. They're pulsing round him in an almost fully formed window.

"How do you know?" Shark asks suspiciously.

"Never mind. That's him. He's almost done. Another few minutes and the window will open."

Shark curses, then starts towards the man with the Mohican. Dervish pushes after Shark, and I head after Dervish. As we're nudging through the crowd, the band howls into a new, faster song and the place goes wild. Suddenly, punks are leaping all around me, bashing into one another, falling over, kicking and punching everyone in sight.

I'm knocked to the floor. Someone stamps on my right hand. I yell with pain. Try to get up, but I'm knocked down again. Struggling, panting, afraid I'm going to be crushed to death by a sea of punks.

Then Shark is beside me, lashing out with his fists, pounding the punks away. Dervish picks me up and gives me a fireman's lift. He's stronger than he looks. "Hold on tight," he says, and we push forward again, Shark clearing a path.

I hit out at a few of the punks, taking advantage of my position, trying to smash a few noses in revenge. Then I remember I've a more important mission and turn my attention to the stage. I have a better view of the demon summoner from here. I see him start to tremble. He froths at the mouth. The lights in the window pulse at the same time.

"Too late!" I shout. "It's going to open."

"No!" Shark roars, shouldering an especially large punk out of his way. "We can make it! I'm not going to - "

An explosion. Part of the stage erupts, showering the people closest to it with splinters and nails. Agonised screams. One of the guitarists falls to his knees, face a pulped, bloody mess. The singer doesn't stop. He's so caught up in his song, he doesn't hear anything except his own voice.

There's a violet coloured window of light next to the Mohican man. He's standing by it proudly, unharmed. He smiles at the chaos. Puts a couple of fingers between his lips and whistles shrilly.

A demon bounds through the window. The body of a large chicken. Three pig-like heads. It looks ridiculous, almost laughable, until it opens a mouth and spits at a nearby punk. The spit hits him squarely in the face, then bubbles and burns his flesh away. He falls, trying to scream, but unable to.

Dervish called for anarchy a few minutes ago - now he gets it. The room was wild with dancing, writhing and fighting before this, but when the punks see the demon in action they go completely mental. Panic sweeps the crowd. Shrieking, they surge for the exit doors. The man with the Mohican laughs and steps up next to the demon.

"Now we'll see who has power!" he shouts over the chaotic screams. "All these years of having to lick somebody else's boots and bow down. No more! Now you'll learn to fear me. This is my world now. All of you - "

He gets no further. The demon, displaying no sense of gratitude, spits at the man. He's flung backwards, the acidic spit already setting to work on his face, dissolving his flesh and cartilage, eating through to sizzle his brain. Who said there was no justice in the world?

We're pushed back and hammered down by the rioting crowd. Shark yells with rage and surprise. He tries fighting them off, but he isn't powerful enough to stand against the tide of panicked punks. I go down again and feel the room close around me. This time I'm certain I'll be crushed.

But Dervish keeps his cool. There's magic in the air - I can feel it seeping through the window. He draws on it, barks a few words and suddenly the space around us is clear, punks wedged aside by an invisible force. The three of us are alone, protected by a bubble of magic energy, like the one Nadia and the others fashioned on top of the needle of rock.

"Shark!" Dervish yells, nodding at the demon, which has spat at a third punk and is now bent over the remains of the man with the Mohican. It's slurping up the spit, along with the gooey mush which is all that's left of the man's skull and brains.

"On it," Shark grunts, stepping forward. He taps into the magic, tenses, then leaps through the air, landing beside the demon. Before it can react, he grabs one of its heads and twists savagely left, then right, ripping it loose.

The demon screeches and spits at Shark with both remaining mouths. Shark ducks out of the way of one of the spitballs and deflects the other with a wave of a magically charged hand. He throws the severed head - still moving - through the window, then grabs for another. This time the demon dodges the tattooed fingers and takes flight, making a noise which is a weird cross between a pig's squeal and a chicken's cluck.

The demon's heading for one of the windows at the front of the building. Before it gets there and breaks through to kill the punks who've spilled out on to the street past the bewildered doormen, Dervish mutters a quick spell. The glass turns to steel. The demon doesn't see this. It leaps, cackling, only to slam hard into the metal and flop to the floor.

Dervish uses magic to clear a path between us and the demon. He darts forward while the demon's shaking its heads with confusion. Gets between the monster and the front door. "Are you sure we can't kill it?" he shouts at Shark.

"Yes!" Shark bellows.

"Then let's force it back through the window." He sneaks a look at me. "Kernel, can you budge over, block its path to the rear doors?"

"I'm not sure," I mutter. "I'm not good at fighting..."

"You won't have to fight," Dervish assures me. "Just look like you know what you're doing, like you're the meanest piece of scum in the room. Scowl. Growl. Howl. If it goes for you, I'll step in."

I trust Dervish, even though I barely know him. He's younger than Shark, but speaks like he's older. So with only the slightest hesitation, I do what he asks and edge my way left, along the path which Dervish is creating. I take up a position halfway between him and Shark, spread my arms, glare at the demon and act as if I'm far more powerful and confident than I feel.

The demon's on its feet. Blood oozes from the neck where its third head was removed. Bile dribbles from its remaining mouths, sizzling where it hits the floor, burning through the old wooden floorboards. It sends a ball of spit zooming at Dervish, but he waves a hand at it and the ball explodes. He chants a spell and several bricks snap loose from the wall and fly at the demon, striking its body and heads.

The demon bats the bricks away, then looks from Dervish to Shark to me. It's searching for a weak point. Its gaze lingers on me, since I'm the smallest. I want to run for cover like the punks, but I don't give in to fear. Instead, I step forward, sneering at the demon, inviting an attack.

The bluff works. With a petulant cry, the demon darts towards the window of violet light, past the singer who's still roaring into his microphone, eyes shut, no idea of what's going on. Shark curses, as though he left the route to the window open by accident. He lunges at the demon. The beast picks up speed, makes it to the window, then leaps to safety, laughing hysterically at Shark, thinking it got the better of him.

"What a team!" Shark hoots, standing to the left of the window, on his guard in case the demon returns. "Did you see that baby run? We kicked its ass royally!"

"What a buzz," Dervish murmurs, closing in on the window, pausing to melt the walls around the front and rear doors, allowing more of the punks to exit - easier than trying to restore order. "I've never felt so powerful. Never knew I could do so much. The magic in the air... the way I tapped into it... unbelievable!"

"You've got the taste for this now," Shark chuckles. "You were nervous earlier. That's understandable. We all get the jitters the first time. But you've caught the bug. It's demon-fighting all the way for you now, right?"

"Maybe," Dervish says, smiling crookedly, looking at his hands with a mix of pride and wonder. "I did most of it without thinking. It was like there was somebody else inside me, pulling the strings."

"The steel windows were a good idea," Shark commends him. "You're more imaginative than me. I'd have tried to drag the demon back."

"How long will the window to the other universe remain open?" Dervish asks.

"Maybe a few minutes," Shark says. "We'll stick by it until it closes, to be safe, then get out of here quick. Try explaining to a policeman that you're part of the great war against demons - see where it gets you!"

Dervish examines the window with innocent curiosity. He pokes his fingers into the light, yelps when they disappear, clutches his hand back and wriggles his fingers, relieved to see them still in place.

Shark laughs. "I did that the first time too."

"Have you ever stepped through?" Dervish asks.

"Once. Came back right away - didn't want to get stuck over there."

"What did you see?"

"A world like ours, only - "

"I have to go," I cut in. They'd forgotten about me. Now they stare. "Beranabus. I've got to get back to him. Remember?"

"You want to step through the window?" Shark frowns.

"No. But I have to. I can find him when I'm in the demon universe."

"What if the monster's waiting for you on the other side?" Dervish says.

I shrug unhappily. "I don't have a choice. I can't find Beranabus here."

"Won't he come for you?" Shark asks.

"Maybe. But I'm not sure he can find me as easily as I can find him. I have to go," I say, urgently this time, aware that the window might close while we're arguing. "A demon stole my brother. I have to rescue him."

I take a step towards the window. Shark puts out a large tattooed hand and stops me. "There's no way I'm going to let a kid walk through that alone," he growls. As my face crumples, he smiles. "So I'd better tag along, make sure you don't come to any harm. Dervish?" He raises a questioning eyebrow.

Dervish studies the window again. Licks his lips nervously. Then nods quickly. "Yeah. What the hell. There's never much to do here on a Saturday anyway."

My eyes fill with happy tears. "Thank you," I mumble.

"Never mind the thanks," Shark sniffs. "Just be ready to fight." And saying that, he grabs the collar of my T-shirt and hurls me through the violet window of light, back into the cauldron of the Demonata.