Still, Rosa did not trust Margaret with her daughter. She did not trust her to take care of her properly, or to treat her kindly, or to cherish her. Ada would not understand where Rosa had gone or why she did not come when she cried for her. Duchess Margaret had made her thoughts on crying babies known several times during previous visits.

‘It does them no good at all to rush to their side every time they whimper,’ she’d said. ‘Children ought not to be mollycoddled. They must learn to be self-sufficient. And if they cry and carry on, then they must be punished. Spare the rod, I always say.’

The thought of anyone striking Ada and then leaving her to sob alone in a chilly, darkened room rose up like a spectre in Rosa’s mind. The image was a hundred pairs of icy hands clutching and squeezing at her insides, poking frozen fingertips down deep into her soul. She gritted her teeth, gave the order to return home and climbed up into the carriage.

It was dark by the time she returned to Raven Hall. She refused offers of food and refreshments from the servants and went straight to her dressing room, where her thoughts turned to the clockwork pigeon. As she had told Beatrice, if the bird was given a letter, it could deliver it to a recipient wherever in the world they happened to be. Yet it would not help now. Ada wasn’t old enough to read a letter, far less write one back to Rosa to tell her where she was. It was hopeless.

Instead Rosa took out the pop-up book. When her garden opened, it would have a magnificent carousel but, in spite of all her efforts, it was not quite the carousel from the book. She went through the pages again now, turning them slowly in the hope that some previously overlooked detail might jump out at her, or an entirely new page rise up to shed light on her dilemma. But the book had shared no new secrets since the invitation.

She had even given up looking for the strange, sad little boy with the withered arm. She had not seen him since that night in the nursery, and Eustace’s conversation with Mrs Wright had proved futile. She was adamant there were no children at Raven Hall.

Finally Rosa put the book away. It was late, but she could not sit in her room doing nothing, so she took the ravens with her and went down to her workshop in the aviary. A team of artificers from her father’s company had worked tirelessly alongside her for the last three months and it had been pleasant having them there, almost like old times. But now they’d all returned to the States, leaving Rosa alone once again.