Teranesia — Greg Egan

Welcome to Teranesia, the island of butterflies, where evolution has stopped making sense.

Prabir Suresh and his younger sister, Madhusree, live in a remote paradise called Teranesia, where their biologist parents are studying an unexplained genetic mutation among the island's butterflies. Then civil war erupts across Indonesia, shattering their idyllic world and their lives.

Twenty years later, Prabir is still plagued by feelings of guilt and an overwhelming responsibility for his sister, now a biologist her-self. Against his advice, Madhusree is returning to Teranesia to solve the mystery of the butterflies and study strange new plant and animal species that have been emerging throughout the region--species separated from their known cousins by dramatic mutations that seem far too efficient to have arisen by chance.

Afraid for her safety, Prabir joins forces with independent scientist Martha Grant to find her. But what he will discover on Teranesia is far more dangerous and wondrous than he can ever fear--or imagine...