Overview: Features interviews with the police to reconstruct the story of how Mark Kennedy went from being a regular south London police officer, with a wife and two children, to becoming Mark Stone. This was Mark the environmental campaigner, militant activist and undercover cop who broke into power stations, learned how to make bombs, infiltrated groups hell-bent on attacking major corporations and stood arm-in-arm with anti-capitalist anarchists. He also had a relationship with a female activist for four years and was even beaten up by fellow police officers who were unaware he was undercover. All the time he was feeding intelligence back to his handlers. Now, with his cover blown, he lives in fear for his life. He is separated from his wife and family. The woman he fell deeply in love with as Mark Stone never wants to see him again. For the first time, Kennedy is returning to face up to himself, his actions and to the people who claim he betrayed them.