I watch the serious-faced paramedics wheel Mum’s stretcher into the back of the ambulance. She looks so small, and I can tell she has no energy left at all. Sylvie climbs into the ambulance after her. This doesn’t seem real. We were meant to land and everything would be fine again.

At the hospital, Dad and I enter the waiting room to see Sylvie walking slowly towards us, looking terribly pale and old. I hear a sharp in-breath from Dad. Is Sylvie about to tell us the worst possible news? I’m not sure my legs will hold me up. I grab Dad’s arm and he pulls me close.

‘They’re giving her fluid and warming her up and doing tests.’ Sylvie slumps onto a chair. She looks up at me. ‘How much energy did she have when you two left the other universe?’

I try to swallow but my mouth is too dry. ‘Not much.’

‘Go outside and find a tree, then try to give her some energy,’ says Sylvie flatly. ‘She wasn’t able to absorb any from me. I think she’s too far gone. But you might have better luck.’

The nurses don’t want to let me in to see her, but Dad insists. My insides turn to water at the sight of Mum lying on the bed, wires attached to her and machines blinking. Her face is the colour of porridge, her arms thin and lifeless on the white sheet. This is not my mother; this is a shell, a doll.

The nurse standing by the bed typing into a computer turns to give me and Dad a soft smile. ‘You can stay for just a couple of minutes,’ he says.

I lay both hands on Mum’s cold, waxy arm and imagine my energy flowing into her, filling her, like I did in the Welsh cottage. But nothing happens. It’s like trying to pour water into a jar with the lid on. I can’t speak for the painful knot of tears in my throat.

Sylvie lays her hand on my shoulder. ‘It was worth a try,’ she says in a quiet voice. ‘You proved me wrong, Tulsi. You made it there, you found her and brought her back. You did well.’ Her eyes brim with tears.

‘Mum,’ I whisper. ‘Please. Take my energy.’

But her face turns an even more terrible grey colour.

One of the machines starts pinging and a doctor hurries in. She presses buttons, and calls over her shoulder for someone to come.

‘What’s happening?’ I ask Sylvie.

Sylvie is gazing down at Mum with a look of piercing love and regret. ‘There’s only one way to save her,’ she says.

The doctor is beside us. ‘I have to ask you to leave.’