We stare at Teacake, who is perched on the marble sphere at the base of the banister. She lifts one front paw and begins to lick it. And I remember. I remember her sitting exactly there, doing exactly this. Only the sun was streaming through the open doors behind me, and my mother was laughing, because she had surprised me so.

‘This is Thalia,’ she says, lifting me to meet the kitten face to face. ‘I found her in the forest, and she followed me home.’

‘I thought we said no pets,’ rumbles my father, stalking down the steps frowning at the kitten.

‘Not a pet,’ says my mother, raising her eyes to his. ‘Far more than a pet, my dear, which you would know if you’d take the time to look closer. Besides, she chose me. As feline things will. And she will be a perfect playmate for Estelle.’

‘Stella?’ Zara whispers. ‘Shouldn’t we stay down here and face him?’

I swallow the lump in my throat. Memories come easy as clouds here, and every time they do, I lose my focus, and forget about Yanny, and what we are doing here. Is that part of the curse? I clear my mind, and something calls to me. The acorn at my throat is warm, and it’s pulling me onward.

‘Not yet. We need to go up,’ I say. ‘Teacake, will you distract him down here?’

She blinks, and drops to the floor, venturing down the central corridor.

The steps are slippery blocks of ice, and they seem to go on for miles. We stare up at them, clutching at the bitterly cold banister. I mutter a few words of magic, and as I step forward, the ice melts beneath my feet.

‘Step where I’ve stepped,’ I whisper to Zara.

‘Magical footsteps!’

‘Just . . . melting ice. That’s all,’ I say. ‘Actually, it’s making it pretty clear where we’ve been, isn’t it?’

At the top of the steps, we look back to see small footprints leading to where we now stand.

‘Let’s get rid of them.’ I gesture at the staircase, recalling the Latin word for melt. ‘Liquescimus!’

The stairs begin to drip, and the great arches of ice on the chandeliers below us glisten with melting ice. I forge on, Zara by my side, and we tread down the corridor over worn, faded carpet that glitters with frost, and my ears are stretched with listening for him, but there is only silence below.

And then the air is torn by the unmistakeable sound of dawn breaking. I frown.

‘It isn’t dawn. Is it? We can’t have been gone a whole day and night!’

‘No, it’s not dawn,’ Zara says, shifting her feet. ‘I need to go, Stella.’

‘What?’

‘Mrs Mandrake told me it might happen, if things ever went truly badly in Winterspell. I went to see her after I left you yesterday. I still had her number . . . She said Rory would use the horn if she had to – it means there’s trouble. You’ve got this.’ She looks at me. ‘Really. You have.’