Tom Billett

At a high-security biological research facility, a scientist is deliberately exposed to a deadly toxin.

Bosco and his agents are gunned down within the walls of CBI headquarters. With two men dead and Bosco in a critical condition, Lisbon and her team race to find the perpetrator. As the investigation progresses, it becomes clear that notorious serial killer Red John is responsible - and he has an assistant inside the department.

An investigation of a missing federal agent's remains leads Brennan and Booth to the Nevada desert, where they become immersed in the underground world of ultimate fighting.

Alison puts on a brave face as she returns to Rosewood High and attempts to repair the damage she inflicted years earlier; Caleb and an old nemesis return.

An undercover operation targeting drug smugglers goes wrong, and Boston PD's homicide HQ is next in the gang's firing line.

Kirsten gets news that will change her life forever; Julie has a secret love affair; a therapist gives Taylor rules by which to live; Che discovers that Seth is not his soul mate.