Richard Franklin reads the exciting novelisation of a classic TV adventure featuring the Third Doctor, as played by Jon Pertwee. Eminent scientist Emil Keller has developed a revolutionary new process for the treatment of hardened criminals. His invention, the Keller Machine, is being heralded as a major scientific breakthrough.But Professor Keller is in truth the Master, and the Keller Machine is much more than a mere machine.Soon the Doctor, Jo, the Brigadier and UNIT are involved in a bitter struggle with the Master, an alien mind parasite, and a diabolical scheme to plunge the world into a Third World War... Richard Franklin, who played Captain Mike Yates in the BBC TV series, reads Terrance Dicks's novelisation of a 1971 TV serial by Don Houghton.