Finally, the doors open with a wheeze. ‘Thank you,’ I pant as I climb onboard.

‘Where’s your Oyster, love?’ says the driver, a woman with her hair in a tight bun.

‘What?’

A young man hurries on behind me and as he brushes past, my fingers give an agonising sizzle.

‘Your Oyster card,’ the bus driver says. ‘Your ticket.’

‘Umm … my mum has it. She’s already on the bus.’ I look down the bus but I can’t see her.

‘All right. Make sure you tap on.’

The whole bus is staring at me. A woman in a yellow coat and head scarf gives me a sympathetic smile, and the young man who came on after me glances at me from under his hoodie.

I make my way down the aisle and see her, sitting at the back, alone on a double seat, looking out the window with that serious way my mother has of regarding the world. I shuffle onto the seat beside her and slide my frozen hands between my thighs.

She turns and smiles. ‘Hi.’

I have to stop myself from launching at her because her voice is my mum’s and her soft eyes are my mum’s, and I just want her to hold me.

But this is not my mum. This woman is thinner and paler, and is giving me the polite half-smile my mum saves for strangers.

Which means that I don’t exist here. I was never born in this universe. My breath catches in my throat and I grip the feather in my pocket. Courage. ‘Hello,’ I say. ‘Um, you’re Merry, right?’

She raises her eyebrows. ‘Meredith. Have you seen me at my shop?’ Her accent’s different. More posh.

I shake my head. I long to rest my head on her shoulder. She would smell the same, I am certain. This is almost unbearable, being with someone who is my mother but who is – also – most definitely not my mother.

‘You haven’t seen my mum, have you?’ I ask. ‘She’s Merry. She’s …’ I wave my hands about, as if that might help explain things. ‘You know about other versions of our lives, right?’ I say. ‘Parallel universes.’

Her eyes widen and she presses herself away from me, against the window. ‘Who are you?’ She looks scared.

I swallow. ‘I guess I’m the daughter you never had. I’ve come from a parallel universe to get my mum. Who’s … well, you, of course. Have you seen her?’ Please say yes.

Her lips are pressed tight and she’s gone white. I remember my mum looking like this when Dad fell from the rigging and was unconscious for a few minutes. But what is Meredith frightened of? Not me, surely.

She whispers, ‘I haven’t seen her.’

I slump back in the seat, tears blurring my vision. Mum, where are you? Please come and find me.