All morning, Orial fretted over her tasks in the Sanatorium, impatient to be away to the Crescent and to Amaru Khassian. But when she had finished, her hands were shrivelled and wrinkled with constant immersion in the hot spring water and with slapping on noisome mineral-mud.

As Orial was drying her damp fingers, Sister Crespine came bustling past and slipped something into her apron pocket.

‘What’s this?’ Orial brought out a little black jar.

‘Calendula balm. Marigolds. Keeps the hands nice and soft,’ Sister Crespine said and, to Orial’s surprise, gave her a wink. ‘Don’t you worry, dear, your secret’s safe with me.’

‘Thank you.’ Puzzled, Orial sniffed the white ointment; it gave off a scent of spring meadows, sweet as new-mown grass. What did Sister Crespine know? How much had her frequent absences been noticed – and remarked upon? Sister Crespine must believe she was keeping a tryst with a secret admirer.

Orial sighed and began to smooth a dab of the soft balm between her fingers. Amaru Khassian her admirer? The thought sent a strange shiver of warmth through her body. But theirs was no conventional friendship; she was the admirer, he the admired. On his side, the arrangement was one of obligation; she knew he would never have troubled to pay her the slightest attention if he had not needed her help.

But what links us?

She had read of an invisible thread of understanding discovered to link certain susceptible individuals. Was it possible that such a link existed between her and Amaru Khassian? Were they like two strings tuned to the same pitch; when one was plucked, the other vibrated too in sympathy?

Orial had devised a number of backstreet routes to reach the Crescent, each one designed to avoid recognition by any of her father’s medical colleagues. She cut through alleyways and hurried along mews, past dairies, laundries and stables where horses whinnied and stamped in their stalls.

She was hurrying along Paragon Mews when she almost ran headlong into a young woman in scarlet riding habit coming out of one of the stables.

‘Orial!’ cried the young woman, reaching out to kiss her on both cheeks. ‘It’s been simply ages. You’re looking a little peaky, my dear.’

‘Alizaeth?’ Orial said, stepping back. She and Alizaeth had been at the Academie for Young Ladies together. She had been dazzled by Alizaeth at school; with her glossy black curls and easy chatter, she had commanded the attention of a circle of admirers. But Orial had grown to realise they had little in common; Alizaeth’s interests lay in balls and gowns.

‘Aren’t you going to congratulate me?’ Her smile had become coy.

‘Congratulate you?’ Orial’s brain had been filled with music; now the shock of encountering Alizaeth had made her mind go blank.