Realising Chin-Lee has been using the power of the Keller Machine to carry out assassinations, the Doctor heads back to Stangmoor, only to find the Master has teamed up with Mailer to stage another riot.
Quest roles:
Richard Franklin(Mike Yates), Nicholas Courtney(Brig. Lethbridge-Stewart), Terry Walsh(Guard (uncredited)), John Levene(RSM Benton), Dave Carter(Grierson), Roger Delgado(The Master), Pik-Sen Lim(Captain Chin Lee), Raymond Westwell(Prison Governor), Michael Sheard(Laurence Scarman), Roy Purcell(President of the Council), Martin Gordon(Prison Officer), Neil McCarthy(Thawn), Eric Mason(C.P.O. Smedley), William Marlowe(Lester), Kristopher Kum(Fu Peng), Cy Town(Dalek Operator), Bill Matthews(Prison Officer), Hayden Jones(Lenny Vosper), Fernanda Marlowe(Corporal Bell), Barry Wade(Prison Officer)