FBI Agent Thomas Mackelway violates serial killer Raymond Starkey's civil rights during an arrest, leading to Starkey's release and Mackelway's demotion. Now, Mackelway is haunted by migraines that blur his reality when he is assigned to track down another killer. This time, the tables are turned when the mysterious killer appears to be targeting other serial criminals. As the investigation deepens, puzzling clues emerge, including strange symbols and meticulous surveillance, pointing to a suspect that seems to be outside their grasp and understanding. The case begins to consume Mackelway as he delves deeper into a world of inexplicable horrors and mind games.

Mackelway enlists the help of his colleague and former lover, Agent Fran Kulok, to make sense of the cryptic evidence. They follow the trail of bodies and are drawn into the web of the enigmatic killer. As they put together the pieces of this dark puzzle, it becomes apparent that the perpetrator might have a larger, more profound motive than just murder. Personal and professional boundaries blur for Mackelway as he becomes further involved in the case, challenging his sense of justice and his very sanity in the pursuit of a phantom-like criminal who always appears to be one step ahead.