The words burst from her, each one dropping like a stone between them, into that open, empty space – a well with no bottom. Her chest ached with the effort of keeping her screams locked inside, her fingers itched to tear at Eustace’s face. In the moist sickliness of the carriage he drew a deep breath. There were circles beneath his eyes and his face was grey. For a moment Rosa wondered whether she had done him a disservice. Perhaps he was distraught by Esme’s death. Perhaps he did care. Perhaps he was about to reach out to Rosa, try to comfort her in some way, even apologise, ask if they might start again. For a moment she longed for him to do so – to make some attempt to put right all that was so wrong between them.

But instead his mouth pinched into a thin line. ‘Mother is right,’ he said. ‘You’re as uncontrollable as a horse without a bit in its mouth.’

‘Your mother doesn’t know the half of it,’ Rosa spat. ‘Do not forget about the ravens, for they have not forgotten you!’

She was pleased to see Eustace shudder at the mention of the birds. Several of them had come on the trip and, much to the driver’s consternation, were riding with him on the roof of the carriage.

She turned away, angling her head so that her travelling bonnet partially shielded her face from Eustace’s view. She yanked back the curtain to stare blindly out of the window. It was so cold inside the carriage that she thought her tears would freeze to her cheeks, but they ran towards her chin and she had to lean down to wipe them on the sable-fur trim of her cloak. Ada howled and howled as Rosa futilely tried to soothe her. Her arms burned from holding her. She wished with all her soul that Ada could be quietly content, just once, just for a few moments of blissful peace.

The snow was storming so thickly outside that she couldn’t see the mountains at all, but she could feel their presence, the silent sentries who cared nothing for the small human miseries passing through them. The invisible valley felt suddenly sinister, shrouded in a sort of doom that made the air heavy and hard to breathe.

The snow smothered everything with a graveyard hush, the only sound the rattle and creak of the carriage, the snorts of the exhausted horse. There was a feeling of pressure in the air, a sense that they had passed out of the real world entirely and into some strange, impossible place, the cruel realm of a heartless ice queen where everything was shards and splinters and spite.