Dellarobia Turnbow is a 28-year-old discontented housewife living with her poor family on a farm in Appalachia. On a hike to begin an affair with a telephone repairman, Turnbow finds millions of monarch butterflies in the valley behind her home.
As the news of her discovery spreads, university professor Ovid Byron arrives to study the monarchs, and warns that although they are beautiful, they are a disturbing symptom of global climate change, displaced from their established winter habitat in Mexico, and that they may not survive the harsh Tennessee winter.
