The story of prosecutor Vincent Bugliosis search to uncover Charles Mansons involvement in the Tate and LaBianca murders of 1969 is dramatically recounted through Bugliosis interviews with witnesses, the murderers gruesome flashbacks, and lively court scenes. Based on the book of the same title by Bugliosi, the film begins with Sharon Tates maid discovering the mangled bodies of the actress and a few of her friends. As the maid flees from house screaming, Murder, murder, the Beatles song Helter Skelter blares in the background. Sirens shrieking, the police reach the scene. After the business manager of Roman Polanski, Tates husband, identifies the bodies, we learn that the police already have Tates caretaker in custody as a suspect. Meanwhile, the LaBianca children return home to find their parents dead and Helter Skelter scrawled across their refrigerator in blood. Three days after the Tate murders and two days after the LaBianca murders, the caretaker is released due to insufficient evidence. Much to the Los Angeles Police Departments frustration, the killer is still at large. One week after the killings, the police raid Spahn Movie Ranch, where Manson and his family, or followers, reside. Yet it is not because they suspect the family for murder that the police raid the ranch, but because the family has been stealing cars. Shortly after the family is arrested, a young boy finds a gun in his back yard, a few miles from the Tate home, and his father reports it to the police. Unfortunately, before police can link the gun to Manson, he and the family are released from prison. The evidence against Manson begins growing once Bugliosi is assigned to the case. Interviewing various members of the family, Bugliosi learns that, while Manson did not commit the murders, he manipulated his family members to kill. After gathering a sufficient amount of evidence to convict Manson, Bugliosi needs only one more piece to the puzzle: Mansons motive. Questioning a former family member, Bugliosi discovers that Manson believed the Beatles were sending him messages through their music, telling him to wage a race war against black people, which he deemed Helter Skelter. Manson figured that if he had his family kill white people, he could blame it on black militants and, therefore, begin the war. Finally understanding Mansons rationale, Bugliosi is able to convince the jury that Manson is guilty. The film ends with Manson and four of his family members incarcerated for life.