Dellarobia Turnbow is a restless farm wife who nurtured worldly ambitions before becoming pregnant and marrying at seventeen. Now, after more than a decade of tending to small children on a failing farm, oppressed by poverty, isolation and her husband's antagonistic family, she has mitigated her boredom by surrendering to an obsessive flirtation with a handsome younger man. Intending to meet him, she finds instead a forested valley filled with a lake of silent red fire that appears to her a miracle. In reality, the forest is ablaze with millions of butterflies. Their usual migratory route has been disrupted, and what looks to be a stunningly beautiful view is really an ominous sign, for the Appalachian winter could prove to be the demise of the species. Her discovery of this phenomenon ignites a media and religious firestorm that changes her life forever. After years lived entirely in the confines of one small house, Dellarobia finds her path suddenly opening out into blunt and confrontational engagement with her family, her church, her town, her continent, and finally the world at large.