Libby, Montana. The late 1980s.
Gayla Benefield reads electric meters for a living. Every day she walks from house to house in her small mountain town, and every day she notices the same thing.
People are home in the middle of the day. A lot of them are on oxygen tanks.
They are not old. Many are in their late 40s or early 50s. They should be at work.
Gayla knows what it looks like when someone can't breathe. Her father died of a lung disease in 1974, after years at the mine outside town. Now her mother is struggling for every breath.
But her mother never worked at the mine.
Gayla starts asking a question nobody in Libby seems to want asked. What is making this town sick?
It would take her more than ten years to get the answer. Along the way, her neighbors would come to hate her for asking.