Dellarobia Turnbow is a restless farm wife who gave up her own plans when she accidentally became pregnant at seventeen. Now, after a decade of domestic disharmony on a failing farm, she has settled for permanent disappointment but seeks momentary escape through an obsessive flirtation with a younger man. As she hikes up a mountain road behind her house to a secret tryst, she encounters a shocking sight: a silent, forested valley filled with what looks like a lake of fire. She can only understand it as a cautionary miracle, but it sparks a raft of other explanations from scientists, religious leaders, and the media. The bewildering emergency draws rural farmers into unexpected acquaintance with urbane journalists, opportunists, sightseers, and a striking biologist with his own stake in the outcome. As the community lines up to judge the woman and her miracle, Dellarobia confronts her family, her church, her town, and a larger world, in a flight toward truth that could undo all she has ever believed.