Kit (Martin Sheen) and Holly (Sissy Spacek) are based on real-life killers Charles Starkweather and Caril Ann Fugate. Kit is ten years her senior but falls for Holly, a teenager who wants to be with him against her father’s (Warren Oates) wishes. After a deadly conflict with the father and then burning down the house, Kit and Holly go on the lam, living in both South Dakota and Montana, and live off of the land. For a while, they live in a tree house that they build in the woods. Kit kills a lot of people and Holly does not get upset by this because she is so deeply in love with Kit. Their life of killing and living out in the wildnerness can't last forever.