UNIT are invited to observe a demonstration of the new TOMTIT machine, unaware its creator, Professor Thascales, is actually the Master.
Quest roles:
Richard Franklin(Mike Yates), Neville Barber(Dr. Cook), Nicholas Courtney(Brig. Lethbridge-Stewart), Terry Walsh(Doran (uncredited)), John Levene(RSM Benton), Roger Delgado(The Master), Wanda Moore(Dr. Ruth Ingram), Ian Collier(The Renegade (voice)), John Wyse(Dr. Percival), Barry Ashton(Proctor)