The New York Times bestselling author of The Secret Book of Flora Lea returns with a novel spanning three generations of women about a famous lost book, a famous lost mother, and an artist searching for both. In 1927, in Bluffton, South Carolina, a famous American--former child prodigy author Bronwyn Newcastle Fordham--disappears, abandoning her eight-year-old daughter and husband. She leaves behind a sequel to her children's fantasy blockbuster about a young girl named Emjie who is caught between worlds. But the sequel is written in the author's secret and untranslatable created language. Now in 1952, Bronwyn's lost words have been discovered in a private library in England by a man called Charlie Jameson. Bronwyn's daughter, Clara Harrington, a children's book illustrator and divorced mother of one, goes on a quest to England to retrieve the lost words of her mother, words she believes will translate the sequel and help her discover what happened and why her mother abandoned her. Clara takes along her own eight-year-old daughter, Winnie, who is precocious, funny, and wise, and who has an imaginary friend, also called Emjie, after her lost grandmother's novel. But when Clara and Wynnie sail to England, they arrive during one of London's greatest natural disasters--the Great Smog. Wynnie is a fragile child with asthma and the air is deadly. Charlie Jameson helps them escape London and make their way to his family's country home in the Lake District, where the tale unfolds in the wild and glorious landscape of Esthwaite Water and the land of Beatrix Potter. It is there that the tangled roots that tie Charlie and Clara together will be revealed, and the fate--not only of Emjie, but of Bronwyn herself--will come to light.