It is 1903 when Thomas Edgar says goodbye to his young wife Sophie and embarks on a journey to the Amazon, where he dreams of finding a mythical butterfly that will make both his name and his fortune. His dreams change, however, soon after his arrival in Brazil …

Months later, Thomas arrives home, thin, sick and, worst of all, unable - or unwilling - to speak. Frustrated by his silence, Sophie takes increasingly drastic measures to uncover the truth about what happened to her husband while he was away. But as she sorts through Thomas’s diaries and boxes of exquisite butterflies, it becomes clear that the truth may not be easy to bear.