2001, New York

The portal shimmered in the middle of the archway, a perfect sphere of energy, and in the middle of it a hint of the ghostly wavering world of a whole forty-eight hours ago: Sunday night. A flickering of neon light and what looked like a twisting, undulating stretch of graffiti-covered brick wall dancing through a heat-haze.

‘Come on, then, Sal,’ said Maddy. ‘Quickly through.’

Sal swallowed back a throatful of nerves and nodded. ‘Yes, all right, I’m ready.’ She stepped forward, feeling the energy lift the hairs on her arms, lift her fringe like a theatre curtain. ‘It tickles!’

Stepping inside the sphere of energy, she could feel the concrete floor beginning to flex beneath her feet, like the canvas of a trampoline somebody else was already jumping up and down on. Then very quickly it softened and sagged like tissue paper … and then all of a sudden the floor was completely gone.

‘Jahulla! I’m falling!’ she yelped as her arms and legs flailed and she felt herself tumbling through air.

‘Don’t worry about it!’ she heard Liam’s voice say, but already it sounded like it had been shouted down a long, long tunnel, distant echoes fast receding. Then it was gone.

‘Liam!’ she cried, but her own voice sounded dampened and swallowed up.

I really am alone.

Just like he’d said, here she was, floating – or falling – through an ocean of featureless white. Like a nugget of breakfast cereal see-sawing down through an impossibly large bowl of milk.

Stay calm, Sal.

Swirling featureless white all around her. She held her hand up only a dozen inches away from her face and it was so faint, fogged by the mist. She waved it around and felt the air, as thick as liquid, resist her movements. She looked up, hoping to see the faint form of one of the others flailing above her, but she saw nothing but more white.

Maybe I AM all alone.

She wondered whether she was in her very own milk-coloured universe, or whether the others were out there somewhere. Perhaps nearby. Perhaps just beyond sight. She wondered if anyone ever got lost in here, never to emerge at the other end. Doomed to spend eternity swirling and flailing. You’d go insane, wouldn’t you? With nothing to see, hear, smell or feel, you’d go completely insane.

She decided it was probably best not to think about this kind of stuff. But then her mind had more unwelcome questions it wanted to ask.

What if that’s what the creepy-movey things are? Other travellers … maybe even other TimeRiders who’ve lost their way? Got stuck here for eternity?

She could all too easily conjure up the image of another girl just like her, lost for endless centuries in here: eyes fogged by madness, opaque like those of a boiled fish, and cackling like an old woman – a mind rubbed smooth of meaningful thought and left utterly, utterly insane.

This really isn’t helping, stupid. Think of something else.

She decided she’d rather she was on her own; catching a glimpse of something out there, faint and moving, was the last thing she needed to see right now, so she closed her eyes.

Almost as soon as she’d done that, she felt the ground suddenly return beneath her feet.

‘Whuh?’ She opened her eyes to see she was standing in a small car park, lit faintly by a neon red BUDWEISER BEER sign that buzzed like an angry fly in a bottle. She took a step clear of the portal and a moment later Liam, Maddy and Becks emerged, one after the other.

‘That was horrible!’ she gasped under her breath.

‘First time’s the worst, so.’ Liam grinned apologetically. ‘Maybe I should’ve warned you.’

She could hear a deep rhythmic pumping sound coming from somewhere beyond the brick wall in front of her. To her left the wall continued past an alcove where cars were parked so tightly in a row side by side she wondered how any of the drivers had managed to get out. The wall came to an end overlooking a dimly lit backstreet where she could see the impatient shifting outline of a queue of people.

‘Oh, it sounds like they’ve started playing already,’ said Maddy. ‘Come on, guys, let’s get inside.’