Ming Qong is convinced that girls have changed the world throughout history.

History's sister, the mysterious Herstory, believes that the more you know about the past, the better you can understand the future. And so she now sends Ming back in time to work as a maid in an isolated English mansion to see a girl change the world in 1829.

But which girl? The young mistress of the house is lying in bed blind and immobile, recovering from the measles. Abandoned by her aristocratic mother and the rest of her family, she may never walk – or even read and write – again.

Ming becomes friends with another scullery maid, Hepzibah, who is desperately teaching herself to read, and who longs to free slaves, as she and her parents had been. But what hope has a scullery maid?