A teenage girl (Thomasin Harcourt McKenzie) and her father (Ben Foster) have lived undetected for years in Forest Park, a vast wood on the edge of Portland, Oregon. A chance encounter leads to their discovery and removal from the park and into the charge of a social service agency. They try to adapt to their new surroundings until a sudden decision sets them on a perilous journey into the wilderness seeking independence and forces them to confront their conflicting desire to be part of a community or a fierce need to live apart.