In the tense thriller The Marsh King's Daughter, a woman with a secret past will venture into the wilderness she left behind to confront the most dangerous man she's ever met: her father. In the film, Helena's (Daisy Ridley) seemingly ordinary life hides a dark and dangerous truth: her estranged father is the infamous Marsh King (Ben Mendelsohn), the man who kept her and her mother captive in the wilderness for years. When her father escapes from prison, Helena will need to confront her past. Knowing that he will hunt for her and her family, Helena must find the strength to face her demons and outmaneuver the man who taught her everything she knows about surviving in the wild.