Twelve-year-old Harriet is doing her best to grow up, which isn't easy since her mother is on medication permanently, her father has silently moved to another city, and her laid-back sister hardly notices anything. They are all still suffering from the shocking and mysterious death of her brother Robin, which happened twelve years ago, and Harriet feels that the family will never recover. Inspired by Captain Scott, Houdini, and Robert Louis Stevenson, she sets out with her only friend Hely to find Robin's murderer in order to punish him. However, what begins as child's play soon turns into a dark and dangerous journey into the menacing underbelly of a small town in Mississippi.