Fleeing from her dangerous husband, Simon Fairbairn, known as 'The Beast of Bampton', Rose moves her children—Jack, Jane, Billy, and Sam—to a secluded home in America, aiming to escape the horror of their past. To maintain their anonymity, Rose adopts her maiden name, Marrowbone. In this new environment, the siblings find solace at a local beach landmark called Red Witch Rock, where they befriend Allie, a girl from a nearby farm. As the story unfolds, a budding romance develops between Jack and Allie, bringing a glimmer of normalcy to their troubled lives.
However, the shadows of their dark past loom large. Rose, suffering from a terminal illness, makes Jack promise to keep their family under wraps until he turns 21. In a poignant moment, Jack discovers a hidden stash of stolen money that their father had kept, contrary to Rose's claims. Following her death, the siblings decide to hide the truth of her passing to protect their fragile existence.
When Simon escapes from prison, he relentlessly pursues his family, leading to a tense moment when he fires a shot into their home. Six months later, Jack takes a trip into town to visit Allie at the library, where they encounter Tom Porter, a business agent vying for Allie’s attention. He informs Jack that he will return to the house to collect Rose's signature and a fee of $200 to finalize the estate transfer. This prompts the siblings to consider retrieving the hidden money to pay off their father's debts, despite Jane's warning that it is tainted.
As the siblings struggle to maintain their secret life, supernatural occurrences begin to escalate. A drop cloth uncovers strange sounds from the attic, which they attribute to the ghost of their father, hinted by Jane. The tension escalates between Jack and Billy over their secrets and Allie, leading to confrontations and secrets being unearthed when Sam ventures into Rose's old bedroom, setting off a series of unnerving events.
Tom, driven by ambition, discovers the truth about Simon's past and threatens to blackmail Jack into giving him the family’s money. As the brothers continue to grapple with their past, Jack experiences harrowing visions, weakened by the weight of their family’s tragic history. The siblings find themselves ensnared in a web of fear and deception, as Allie starts to piece together the unsettling truth about Jack's dark familial legacy.
As the climax unfolds, Simon confronts the siblings in the attic, leading to a tragic outcome that leaves Jack devastated. With his siblings in peril, Jack must face the terrifying reality of their intertwined fates. Battling inner demons, he imagines his departed siblings urging him on until the ultimate confrontation with Simon occurs, resulting in a violent clash.
Twelve weeks later, as Allie visits a doctor regarding Jack's mental health, there is hope that he is beginning to heal from the trauma. Yet, the shadows of the past still linger, as Allie chooses to keep the memory of Jack's siblings alive for him, gifting him a framed photo while hiding the medication meant to stabilize him. Ultimately, the story explores the boundless lengths one would go to protect loved ones and the haunting specter of an unresolved past that echoes within the walls of the Marrowbone home.
