“Ah—the ‘hated stain’ of transport. I read that they changed the name from Van Diemen’s Land to lessen the unsavory association with criminality.”

“Well, that wasn’t the official reason given, but . . . yes.”

“What was your mother’s offense, if you don’t mind my asking?”

“Stealing a silver spoon.”

Dr. Garrett gave an exasperated sigh. “This is why we can’t leave the making of laws to men. They result in travesties of injustice that unfairly burden the poor. And women. Those high and mighty aristocrats, in their black robes and powdered wigs—they have no idea.”

Ruby had been to Melbourne once, on a summer holiday, but had never imagined a city as vast and sprawling as London, with its north and south banks bisected by a winding canal and linked by half a dozen bridges. (She was surprised to discover that London Bridge, familiar from the nursery rhyme, was quite intact.) She shared a room in a boarding house on Wimpole Street with another of Dr. Garrett’s protégés, a young woman from the Lake District whose family believed she was employed as a ladies’ maid. In fact, as Dr. Garrett pointed out when she arrived, Ruby was the only one of her students whose parents encouraged her desire to become a doctor. “It is my sense that, despite its hardships and limitations, living in a new world accords one certain freedoms. Social hierarchies are not as rigidly enforced. Would you agree that this is true?”

“I don’t know,” Ruby said. “I’ve never lived in any other world.”

“Well, now you will, and you can see for yourself,” Dr. Garrett said.

In her free time Ruby explored the sights, from the British Museum to St. Paul’s Cathedral, from verdant parks to bustling teahouses. She sampled strawberryade and fried fish and chips at an outdoor market in Covent Garden. She attended a performance of The Tempest at the Lyceum Theatre and a trapeze show at a pleasure garden in North Woolwich. On one such outing she found herself in front of the imposing stone fortress of Newgate Prison and remembered the stories that Olive, her mother’s friend, had told about life inside its gates—how she’d met Evangeline there and found herself sentenced to transport on the same ship. How a Quaker reformer handed out Bibles and hung tin tickets around their necks—one of which Ruby had brought with her, wrapped in an old white handkerchief, to London.

During her last week with Dr. Garrett, Ruby visited an orphanage. Stepping inside the front gate, she felt lightheaded. She’d never been able to remember much about her early years at the Queen’s Orphan School in New Town, but now she had such an overwhelming sense of panic that she thought she might faint.

Dr. Garrett gave her a curious look. “Are you all right?”

“I—I’m not sure.”

“Let’s sit for a moment.”

On the settee in the reception room, at Dr. Garrett’s insistence, Ruby tried to identify the feelings that had dredged up, seemingly out of nowhere: dread and anxiety and fear.