Orange monarch butterflies have been thrown out of their natural habitat in Mexico and have settled on the trees of a mountain in Appalachia. The woman who sees them, Dellarobia, feels she has been saved from her own dangerous, destructive impulses by the beauty they offer. When others find out about the butterflies, they consider her blessed, touched by the divine, and a celebrity. A scientist and his grad helpers come out to observe and record the habits and probable death of the butterflies.
The flight and fate of the butterflies symbolizes and comes to presage the fate of the town to which they have fled, offering a warning of what is in store for the USA and the world.