The butterfly dropped the envelope into her hands and then fluttered over to land on the back of a dining-room chair, where it spread its magnificent wings. As Rosa watched, they proceeded to change colour, cycling through dusky lilac to snowy white to ice-blue – an entire rainbow of winter colours. And the creature seemed to affect the objects around it too, because the chair on which it perched changed shades along with the butterfly. Finally its wings turned ivory with lace-tipped edges, and it flew back out of the window to be swallowed up by the sky, which was almost bursting with the promise of further snow.

Rosa turned her attention to the letter in her hands. As soon as she drew out the card, she saw that it was not from the Spider Queen after all. In her haste to open it, she hadn’t noticed that the seal on the back was different. Instead it was another invitation, bordered in tiny pressed flowers:

Lady Beatrice Sitwell is pleased to invite you to the grand opening of her winter pleasure garden tonight.

Prepare to be amazed.

Prepare to be enchanted.

The gardens of Half Moon House are for those who desire more magic in their lives, and will open at 11 p.m. for one hour only.

Rosa frowned. One hour? Most pleasure gardens opened in the afternoon and continued until early morning. Eustace’s pleasure garden had closed at 4 a.m., and the popular gardens like Vauxhall and Cremorne had similar hours.

She flipped over to the back of the card to see if there were any further details, but found only a handwritten note from Beatrice: I am sorry we quarrelled. Please come.

And then the flowers on the border of the invitation started to move. Before her eyes, their pressed petals slowly unfurled and the dainty flower heads grew up towards the sky on a long green stem, until the card contained an entire miniature garden, filling the air with a delicate perfume. Rosa wondered whether Beatrice had selected the flowers especially for her, because they were a mixture of purple hyacinths, the flower of forgiveness, and chrysanthemums, the flower of friendship.

Rosa set the invitation down on the table and smiled grimly. She had no doubt that Beatrice had many spectacular things in her garden, but so did she. And she was fairly confident that a few magic flowers couldn’t possibly compete with the wonders of her clockwork.

After breakfast she went straight to her workshop. The morning stretched on into the afternoon and she was just putting some final touches to one of her new clockwork creations when a footman came to inform her that the family doctor was waiting for her in the drawing room. Rosa had not seen Dr Livingstone since the dreadful time when Esme had fallen ill, and she shuddered at the thought of speaking to him again now.