Dellarobia Turnbow, an unhappy young farm wife living in Feathertown in Appalachia, is about to embark on an extramarital affair when the sight of a blazing orange forest changes her mind. It turns out the startling sight is caused by millions of Monarch butterflies covering the trees, far from their usual winter home in Mexico. The biological oddity attracts widespread attention, and theories about its cause range from an act of God to a world gone haywire from climate change.
Dr. Ovid Byron, a butterfly expert, comes to Feathertown and sets up a temporary lab to study the insects. Dellarobia, prevented from attending college by a shot-gun marriage at age 17, gets a job helping Dr. Byron and becomes engrossed in the research. This, in turn, magnifies the tediousness and poverty of Dellarobia's everyday life.
The book is partly a treatise on the dire consequences of climate change, and partly a character study of the Feathertown people, who tend to reject scientific explanations for changes in nature, regarding them as God's will.
The book didn't have a strong plot in the usual sense but the characters were interesting and the dangers of climate change were boldly drawn. It's not my favorite Barbara Kingsolver book, but it's well-written and worth reading.