Hanna notices some suspicious activity at a nearby cabin while she's kayaking by herself in a remote lake. Believing the woman and her daughter staying there might be in danger, she notifies the authorities. After the authorities find nothing wrong or unusual, they brush off Hanna. When she looks in on them, it sets off a deadly cat-and-mouse game of survival.
This is the story of the feud between FBI Director J. Edgar Hoover and the Kennedys. It shows how much Hoover hated them and how they tried to stand up to him from the day John Kennedy was elected President until Bobby was assassinated.