A notorious serial killer, who was never apprehended, leaves behind cryptic clues and messages signed ‘BSP’ after swiftly killing each man and brutally torturing his female victims to death. In a particularly personal case, the detective leading the investigation discovers his wife murdered, with his young daughter forced to witness the crime. Three decades later, the daughter, now a police detective herself, remains fixated on the case that drove her father to madness. When a new series of murders begins, she becomes convinced that it’s the work of a cunning copycat rather than BSP himself, yet the perpetrator consistently outwits her. He also makes it clear that she is intended to be his final victim. Her obsession and arrogance lead to strained relationships with her colleagues, ultimately resulting in her suspension as the FBI takes over the investigation.