A historical children's book set in the 19th-century with just a bit of stuff not mundane.
It opens on Maud being punished by being locked in the lavatory of the orphanage. She is singing defiantly, and the voice of a strange woman asks after her. She is let out by a Miss Hyacinth Hawthorne, and brought to the office where Miss Judith Hawthorne is waiting: the women she knew were coming to the orphanage to adopt a girl a few years younger than her -- but Hyacinth thinks she's perfect and sweeps off with her.
On the train, they tell her she has to be a secret, and hide in their house, so that no one knows she's there.
At their house, she has new clothes, and all she can eat for meals, and books and education, but she starts to learn things about them, and their third sister. For one they are not so rich as they look.
What weaves onward from their involves making a crocodile out of sand, Maud's taking a train journey alone, a carousal, a drowned little girl, a man who wants permission to remarry, a glockenspiel, a deaf maidservant and the difference between lower-class and upper-class letters, the jetty at the shore, and much more in a dramatic tale.