Set in post-famine Ireland, the novel follows English nurse Elizabeth Wright as she cares for a supposed miraculous girl, who has survived without sustenance for four months.
In the 1850s, Lib Wright, an English nurse trained by Florence Nightingale in the Crimean War, accepts a mysterious job in Ireland.
Lib comes to realize that she and a nun have been hired to watch over an 11-year-old child, Anna O'Donnell, who stopped eating on her 11th birthday four months ago.
Lib immediately assumes the child is a trickster, but is shocked by her deep faith and her insistence that she is existing on manna from Heaven.
From their discussions, Lib comes to realize that the manna Anna spoke of was chewed-up food, fed to her through her mouth by her mother in the evening and the morning under the guise of a kiss.