He falls to his knees with a groan and holds his hands up like a shield. ‘Don’t hurt me!’ he calls.

‘Well, don’t follow us,’ I say. ‘And go and tell the police to let the two other kids go. Or I’ll come and find you.’

He nods. ‘Okay.’

I’m surprised – and a little dismayed – at how good it feels to make this man afraid of me.

I hurry to catch up with Claudie. ‘I can’t believe we got to stay there only two nights,’ she says gloomily. ‘Where do you live?’

‘Oh … far away. I arrived in London this evening.’

She stops walking and turns to face me. ‘Why are you so interested in the circus?’ She uses the corner of her cape-blanket to wipe snow from her face. It’s falling more thickly now, in big, fat flakes.

‘Well … I’m very into magic,’ I say, finally. ‘You know, tricks …. and stuff.’

‘The only magician I know is Sylvie, so I’m not at all into magic,’ she says.

‘Fair enough,’ I say.

When we reach the road where I met Haz, I say, ‘Listen, it’s hard to explain, but it’s really important I find Merry. I think she’s around here somewhere – or she was, three weeks ago.’

‘If she lives around here, the people at the magic shop might know her,’ says Claudie, pointing over the road. ‘She’s a magician’s daughter, so she’d be into magic, right? The shop’s closed now, but they’re nice people. Haz goes there to read the books and watch card tricks.’

I don’t know how I missed the Ultimate Magic Shop when I landed. It’s painted red, and in the window is a lit-up, life-sized model of a wizard in a star-spangled cape. I’ve seen these kinds of shops before. I know what they sell: witch costumes and plastic wands, and props for simple tricks. But Claudie’s right, the owners might know the Merry from this universe, because she would definitely still be into magic.

Above the row of shops are three storeys of apartments, the windows glowing with a cosy, yellow light. If only this Claudie could have a home like that. Or a little van, like my Claudie lives in, decorated with spotty curtains and purple bunting.

We knock on the door of the closed shop but no-one answers. Inside, a small stage is draped with red velvet curtains. Did Mum come here and touch the curtains, thinking of home? Oh, Mum, where are you – and are you all right?

A curious musical chiming begins in the distance. ‘What’s that?’ I ask.

‘Big Ben. A clock on the other side of the river.’

The chiming is followed by six bongs. That means it’s six in the evening here and … I check Sylvie’s watch. Five in the morning at home. I have twenty-three hours left to find my mum.