Lib Wright, a young English nurse, arrives in an impoverished Irish village on a strange mission. Eleven-year-old Anna O'Donnell is said to have eaten nothing for months, but appears to be thriving miraculously. With tourists thronging to see this child, and the press sowing doubt, the baffled community looks to an outsider to bring the facts to light. An educated sceptic, trained by the legendary Florence Nightingale and repelled by what she sees as ignorance and superstition, Lib expects to expose the fast as a hoax right away. But as she gets to know the girl, she becomes more and more unsure. Is Anna a fraud, or a 'living wonder'? Or is something more sinister unfolding right before Lib's eyes - a tragedy in which she herself is playing a part?