Throughout the film, the central mystery questions whether Frank Carter is orchestrating new kidnappings from his prison cell or if an imitator is active. It is revealed that Carter had a hidden disciple and biological connection: Francis Jr. (Owen Teague), Carter's final, unrecorded psychological victim who was groomed to perpetuate his horrifying rituals.
Francis Jr. abducts Jake Kennedy to record a final audio tape before killing him, mirroring Carter's historic modus operandi. Pete Willis and Tom Kennedy decipher Carter's coded references and trace Francis Jr. to a secluded hideout. Pete confronts Francis Jr., recognizing him as the missing piece of his original investigation, while Tom successfully rescues Jake alive, breaking the murderous cycle.
Director James Ashcroft frames the conclusion as bittersweet rather than purely triumphant. Francis Jr. is framed as a tragic byproduct of Carter's maliceβa victim converted into a perpetrator. While Jake is reunited with Tom, Pete carries the weight of past losses, though father and son finally begin a path toward mutual reconciliation and healing.