The Master, in the guise of Professor Thascalos, has constructed at the Newton Institute in Wootton a device known as TOMTIT - Transmission Of Matter Through Interstitial Time - to gain control over Kronos, a creature from outside time. The creature is summoned but proves to be uncontrollable.
Jon Pertwee
as The Doctor
Katy Manning
as Jo Grant
Roger Delgado
as The Master
Nicholas Courtney
as Brigadier Lethbridge-Stewart
Richard Franklin
as Captain Mike Yates
John Levene
as Sergeant Benton
Ingrid Pitt
as Galleia
Wanda Moore
as Dr. Ruth Ingram
Ian Collier
as Stuart Hyde
John Wyse
as Dr. Percival
Neville Barber
as Dr. Cook
Donald Eccles
as Krasis
