A busy city street. Nadia's lying on the pavement. A woman and child are getting to their feet close by. She must have knocked them over when she crossed into this world. Other people are staring at us and the window of red light, mouths open. Cars are slowing as they pass, drivers and passengers captivated by the spectacle.

"Close it!" Nadia yells. I don't need telling twice. Before the vulture-headed demon can follow us, I dismantle the window.

Nadia's on her feet. As soon as the red light vanishes, she grabs me and runs. We race through the crowd of startled bystanders. Nobody tries to stop us.

We turn a corner, race down another busy street. Nadia leads me across the road, weaving through traffic, wincing at the blaring horns but otherwise taking no notice of the cars. Another corner, then another. Finally, in a quiet alley, she stops, releases me, squats beside a wall, leans her head against it, stares up at the clear blue sky - and whoops.

"We did it! You're a genius, Kernel! You got us out!" She looks at me with happy tears in her eyes. "I don't know how I'll ever repay you."

I smile at Nadia, then frown and look around nervously.

"It's all right," Nadia, reassures me. "They can't track us. We're safe. We're alive!"

"Raz isn't," I note quietly.

Nadia's smile dims. "That was a shame. I liked Raz."

"And what about Beranabus and Sharmila?" I ask, guilt setting in. "We ran out. Left them to the demons. We should go back and - "

"No!" Nadia snaps. "No going back." Her eyes glitter. I take a step backwards - she looks like she's going to attack. She notices my fear and relaxes. "Don't worry. I won't hurt you. But we're not going back. We couldn't do any good if we did."

"But... the others?"

She shrugs. "Beranabus will probably survive. He's come through worse. He'll wriggle free somehow. As for Sharmila..." She sighs. "Maybe Beranabus will save her. Maybe not."

She stands and looks at the sky. Lightly runs a finger across her cheeks, caressing the spots and acne scars. "It's warm. Must be late spring or summer. Maybe it's June. That's my favourite month. It's when I was born and when Beranabus took me. I was out walking, a perfect June day, dreaming about my birthday, presents and the future. Looking forward to growing up. I was a plain child, dowdy. But my father said I was an ugly duckling, that I'd turn into a beautiful, glamorous swan one day.

"I was thinking about that - longing for it - when Beranabus spirited me away. Dropped me into the universe of the Demonata. Explained how important I was, all the lives I could save, the good I could do. Offered me no choice. Robbed me of my dreams of a happy future."

Nadia's expression darkens. "He shouldn't have taken me so young. I hadn't seen enough of the world. If he'd come when I was older, I'd have joined him gladly. But taking me like he did... stealing me like that demon stole your brother... it was wrong. Don't you agree, Kernel?"

I stare at her uncertainly. Now that she's mentioned Art, it drives home the fact that I didn't just run out on Beranabus and Sharmila. I deserted my brother too. Left him in that nightmarish universe. Alone in the hands of Cadaver.

"We have to go back," I say softly.

Nadia doesn't hear - or pretends she doesn't. "I wonder where we are?" she says brightly. "London? New York? Paris? Vienna? The world's changed so much since I left, I suppose I wouldn't recognise the cities I visited when I was younger. But there must be parts which are the same. I hope this is - "

"Nadia," I interrupt. "We have to go back. Find them. Help them if they're still fighting, link up with them if they've escaped."

"And if they're dead?" she answers, not looking at me.

"I don't know. Search for Art by ourselves, I guess."

She laughs. "You're brave but stupid, Kernel. You wouldn't last five minutes in that universe without Beranabus. You're good at opening windows but not at fighting. What would you do if you caught up with Cadaver? He'd rip you to shreds without breaking a sweat."

"But... Art... I have to - "

"Your brother's dead," Nadia growls. "Cadaver probably killed him on that first world and fed his body to one of the trees."

"No," I moan. "He's alive. I sense it."

"You want to sense it," she corrects me. "You want him to be alive, so you've convinced yourself he is. But think about it. Why wouldn't Cadaver kill him? He was on the run. He wouldn't have time to play nursemaid to a squalling baby."

A kid on a skateboard turns into the alley and whizzes past us. Nadia stares at the skateboard, head cocked, probably in much the same way that I stared when I first saw a demon.

"I've missed so much," she mutters. "The world's moved on while I've been fighting. So many places to see. So many things to do. Is it true you can fly anywhere now, in aeroplanes?"

"Nadia," I try again, "Beranabus needs us. We can't abandon him."

"Why not?" she retorts. "You've only known him five minutes. He treated you like a slave, the way he treats everyone. What do you owe him? Why throw your life away on his account?"

"I need him to help get Art back. I can't - "

"Stop talking about your brother like he's alive!" Nadia shouts. "Let him go. Admit he's dead. Move on. You can go home - I'll help find your parents. Forget about the Demonata. Pretend it was a bad dream. That's what I'm going to do."

"I can't," I say stubbornly. "Art's alive and I'm going to find him."

"You'll go back?" she asks mockingly. "Face the demons? Die like Raz? You didn't know what you were stepping into when you followed us through the first window. Now you're better informed. Do you really have the courage to cross universes freely?"

"I have to," I mutter. "For Art."

"I don't think so," Nadia says coldly. "You ran. The time to fight has passed. You feel guilty because you didn't stand by Beranabus and you want to put things right. But if you think it through, you'll see that's madness. You don't want to go back. And you won't. You'll stay in this universe, where you're safe. Like me."

I stare at the ground, tears creeping down my cheeks. Everything she says is true. I am afraid. I don't want to go back. I'm a coward.

But despite all my weaknesses, I have to return. Because I love Art more than I fear demons.

"Come with me," Nadia says, taking my hands. She's smiling, looking prettier than normal, hair shining in the sun. "I'll take you back to your parents if you want or you can stay with me. I'll be a sister to you. We can travel the world together. I'll use my gift to make money. We'll stay in the best hotels, sail the seas on mighty liners, fly through the sky on aeroplanes. Anything you want, I'll give you. It will be a precious life. No worries, no fears, no demons."

I shake my head slowly. "I can't," I croak. "Art's my brother. I can't abandon him."

Nadia scowls and releases my hands. "Have it your own way, fool! But when you're dying beneath some hideous demon, watching it reel your guts out like a cat playing with a ball of string, remember what I offered you."

She turns on her heel and marches away.

"Nadia!" I cry. "Where are you going?"

"There," she says, waving a hand at the world in general.

"Don't leave me," I wail. "I don't know where we are. You have to help me find Beranabus. You can go after that, but..."

She turns a corner and storms out of sight, leaving me in the alley. Alone.

I'm sitting on the dusty ground. Hands on my knees. Head on my hands. Crying. It's been maybe an hour since Nadia left. I kept thinking she'd come back, that she'd decide she couldn't desert me. But there's been no sign of her. And the more I think about what she said, and her face when she said it, the less chance I think there is of her returning. Nadia hated her life with Beranabus. She went along with him because she had no other choice. But then I gave her a way out and she leapt at it.

Eventually, when the tears stop, I get to my feet and look around. I feel hungry now that I'm back in my own world, but there's no time to eat. I have to find Beranabus - if he's still alive.

There are dozens of patches of light hanging in the air around me, but none are pulsing. I wipe my cheeks clean, then focus. "Beranabus," I mutter, thinking about his face, his shabby suit, the flower in the buttonhole, his clean hands. I repeat his name, over and over, waiting for the lights to pulse.

Nothing happens. The lights maintain their steady glow.

I go cold - maybe that means he's dead!

"Art," I say quickly, fixing my brother's features in my mind. I concentrate on his name and face, but the lights don't change.

My stomach's tight with fear. Are they both dead, slaughtered by demons? They must be. Otherwise, why wouldn't the lights pulse and lead me to them?

I have another thought, just before panic sets in completely. I visualise Cadaver's horrible features and say the demon's name, time and time again. Nothing.

The fear drains out of me as I realise the lights work differently here. They don't pulse when I think of a person or place. The magician and my brother might still be alive.

Relief floods through me - then drains almost immediately. Because if the lights don't work the same way here, how will I find Beranabus or Art, or open a window to the universe of the Demonata?

I can't get back.