He offered her his arm, Rosa reluctantly placed her gloved hand in the crook of his elbow and they went outside. There was applause when they emerged, eager eyes turning towards them in the dark, necks craning for a glimpse of the esteemed couple. Rosa smiled and inclined her head in acknowledgement, amazed at how easily the old gestures came back, startled by the familiar buzz of conversation and the cold press of a champagne glass through her silk glove.

And what a transformation in the gardens – like a dark butterfly unfurling its wings as it emerged from a night-time chrysalis. The first and most overwhelming impression was created by the sparkling lights: hundreds and hundreds of them. Coloured oil lamps hung among the trees, candles flickered on tables, but best and brightest of all were the clockwork peacocks.

The blue-and-green eyes of their spectacular feathers blazed with an astonishing brilliance that surpassed all else. Sparks of sapphire and emerald flashed inside the female guests’ diamond necklaces, and a blue haze bathed the plumes of ostrich feathers in a ghostly glow. The peacocks’ elegant blue heads and necks shone with an iridescent sheen, as if they’d been dipped in oil, and their golden eyes glowed just as brightly as the ones on their feathers.

Rosa and Eustace took their dinner in one of the supper booths. They were situated in a grove of flowering Aesculus x carnea, or pink horse-chestnut trees – the only ones in the whole country. Plenty of homes and gardens had horse chestnuts, but none that flowered pink. They were one of the many exotic specimens that Eustace’s plant hunters had brought back from the continent last year.

The orchestra’s music seemed to float through the air on wings. Patriotic paintings lined the wooden walls of the booths, showing heroes bloodied in victorious battle. Beyond the lights, the silhouettes of the monkey-puzzle trees were dark sentries gazing down at them. The food was as excellent as ever, yet the chicken skin seemed to sit greasily in Rosa’s stomach, the champagne created too many bubbles, the syllabub – normally her favourite – was a slimy sludge in the crystal-cut bowl. Her pregnancy had ruined so many of her favourite foods for her, but she forced down as much as she could, before the ordeal of mingling with their guests began.

There were perhaps two hundred people there, and Rosa and Eustace spoke to each and every one – including, unfortunately, the dowager duchess Margaret, who had made a special trip down from London for the event. Rosa found herself mentally switching off as Margaret expounded on what she must, and must not, do during her confinement. Truly she had never known a woman to be an expert in so very many areas; and, in her sweetest voice, she said so. Eustace missed the edge in her tone and looked pleased, but Margaret was a little sharper than her son and knew it was no compliment.